A few narrow points

The conclusions don't necessarily create the idea that conservatives have figured out how to address the concerns of women (or single mothers in particular). But there were a few morsels of ideas and concessions in here (of course, Frum isn't widely considered a conservative by other conservatives). 

"the pro-life movement really does seem to have changed American minds about the morality of abortion. Only about one-fifth of Americans wish to see abortion outlawed—a proportion that has remained steady since the mid-1970s. But the proportion that thinks abortion is wrong has edged up over the past 15 years: Only 38 percent of Americans now describe abortion as “morally acceptable.”"

- This trend explains much of the strategy behind most abortion restrictions as if most people seem to think what is being done is wrong, but aren't willing to ban it outright, the restrictions will sound like sensible methods of "getting people to think again" while ignoring the actual impact of the restrictions. It's also why I think that if Roe were ever overturned, pro-lifers are screwed as they have to defend the idea that not only is it "wrong", but it should be illegal. A prospect which is not a clear line for crafting jurisprudence, as evidenced by our fraught history waging the drug war, or Prohibition before that, among other examples. It seems even less likely to lend itself to clear jurisprudence where metaphysical assessments of the origins and meaning of human life are concerned, and these become intertwined in a variety of scientific or natural phenomenon (such as miscarriages).

The major problem with the trend is that it does two things.

1) Confuses the population's terminology and labels. "Pro-life" is more broadly interpreted than "someone who wants to ban abortion". "Pro-choice" is mostly becoming limited to people who don't want to describe themselves as "pro-life". The popularity of both labels gives the basic impression that the ardent pro-life position, or the ardent pro-choice position, are more popular than they really are. The vast majority of people are instead in a fuzzy zone and have few strong opinions other than that "it seems wrong", or something to that effect (the famous Clinton formulation of "safe and legal but rare"). Neither position should have much dominance if popular will is sufficient to argue the legal merits of abortion (I do not believe it should, and possibly even pro-life persons would agree with me on that point when they recognize that they do not stand before the majority).

2) In truth, both labels are functionally meaningless. By acknowledging that neither position does hold sway, we should be able to acknowledge properly that most other people are not in some carefully thought out and fervently advocated position on this issue and will hold neither "pro-life" or "pro-choice" politics as a result. If most people seem on simple reflection to agree that we should have fewer abortions because they are "wrong", then the actual disagreement is over what methods would best produce that outcome of fewer abortions, and not so much over the labels we use to argue to that result.

Frum's piece points out, without actually refuting, the standard pro-choice liberal narratives. Access to birth control and various restrictions on abortion account for example for why Europeans have fewer abortions than Americans (often much fewer), or for why the teen pregnancy rate has been falling as a source of decreased demand.

In addition, regardless of whether these factors decrease abortions significantly or not they may have positive effects on these concerns about the "traditional family", such as by allowing women (or potential husbands brought on by "shotgun weddings") to attend college or university and get a degree or decent job instead of attempting to raise a child on a lower-income education and salary. And increased use of birth control has beneficial effects within families, as indicated large numbers of abortions are to women who already have children, indicating unplanned or undesirable pregnancies possibly from inadequate birth control or lack of use, or by decreasing the spread of sexually transmitted disease. We might say those are positive externalities brought on by the use and accessibility of both birth control and to a lesser extent abortion.

Frum's basic argument seems to be that the problem is that in the narrow focus on abortion, social conservatives have confused away the arguments for marriage (and in a related story, also did so by trying to argue against same-sex marriage, and have mostly lost or conceded that fight). In theory such an argument does not actively offend anything. It seems unnecessary in theory to press an active social case for women to be married, whether to men or women, in order to raise children versus the legal and political arguments. In practice there may be merits to it as the "marriage" crisis, such as it is, is largely a problem of the lower socio-economic class who either do not get married or may marry younger and get divorced sooner, and is also less likely to use birth control (but not abortion), and as a result, creates a significant population of mostly poorer and poorly educated single mothers. The upper-socio-economic class gets married later, typically after educations and careers are well-in-hand, and tends to not have children prior to that point. We are also likely to see these as cyclical effects for single-parent homes to produce children who receive poorer educations and thus poorer economic opportunities (among other possible difficulties in childhood).

Having diagnosed this as a potential social ill worthy of attention however, Frum's solutions are more to fret over how we may encourage marriage or to experiment with incentive structures rather than regard the economic and educational choices of people within these single-parenting problems as problems worthy of solution in their own right prior to advancing the agenda of "get more people married" as a second order problem that may help resolve these struggles but which may be considerably more difficult without addressing these structural problems underlying the decisions not to marry for many. These problems can be innumerated thusly:

1) Social welfare safety nets often scale poorly, providing bad incentives to improve the economic state at the marginal position of poverty. Foremost among these with a poor structure is typically state subsidies for day care. Food stamps typically phase out more smoothly. Housing and childhood assistance does not. This can impact household structure by limiting the total household size. This can have the effect of preventing marriages because the marginal assistance from the state declines much more than the amount of additional income provided from a second parent, or failing that, it can have the effect of preventing one or both parents from working at various points during a year to avoid a loss of subsidies.

2) Time management in parenting is a tremendous problem with the attending demands of raising small people into adults. This was previously resolved by two-parent households where one parent (almost always the mother) stayed home to handle most of the home and parenting duties. This is neither as straightforward an option as it was in the 1950s imagination land of conservatives (because often women may have better educational or employment options than the fathers of children), nor something that is always possible even in two parent households today (requiring both incomes for sustainable lifestyles). The solutions here are fairly well known; access to day care (many ways to achieve this), access to flexible scheduling in more occupations (so that parents can take time to deal with home concerns), and some variety of parental or family leave time (whether paid for by employers or the government). With other possible assistance measures like moving back the start of the school day added in for good measure.

3) Because of poor time management flexibility, attaining an education or license for a better occupation can itself be a considerable stretch of this valuable resource (time). We have attempted to resolve this by subsidizing college education costs, but this typically has resulted in ballooning education costs and more student loans rather than more practical outcomes; like well-trained professional skills accruing to graduates. Additionally, since the focal problem is dealing with under-educated poorer people with limited time, such a focus on providing access to college educations is ridiculous as a solution. Most such people, whether from ignorance or time constraints, will not succeed in obtaining a degree no matter how much money is thrown at the problem (within reason). The fix for that requires addressing disparities in K-12 education, not in trying to repair the damage much later, after the fact.

Instead of this focus on college education, fewer jobs or professions should require occupational licenses, along with any accompanying educational requirements, from the state. If they do require licensing from an employer, or there is a potential market benefit to advertise having achieved special training in the craft or art involved, that should be a separate matter. But with the state providing a clear hurdle to entry of various professions, this prevents many people from starting competing or side businesses that they could in fact do things like time management (by largely working from home for example) or to use the profits to fund an education for themselves or their children.