This is something that is not immediately obvious to many conservative commentators, including far right ones, because the acceptable fringe subcultures who are anti-college but still married with kids are very loud and are in fact massively overrepresented in conservative media. There’s also demographic lag, since the true culmination of college as guaranteed path to motherhood in the married class didn’t really hit until the internet era and there’s a lot of women who had babies in the 80s and 90s whose experiences 20+ years ago as non-college married mothers are also overrepresented.
Conservatives are in a real bind by relying on college as the baby factory, though. The number of first births is declining year after year and is not in fact being offset by increases in third and higher births by women who are already mothers. The conversion of middle class parenting and childrearing into a college-microcosm, where all interactions are mediated by a credentialed array of third parties (you don’t teach your kid domestic skills informally, they go to cooking and sweeping and mopping classes) and there is, simply, no organic social interaction (you have to join groups that meet at specific times for specific kinds of “play-based movement”) has been fertility inhibiting and it’s getting more and more so each year.
Even meal preparation has taken on college norms, consisting of carefully measured meal kits to be prepared according to precise and “scientific” instructions, or literal cafeteria-style eating in a upscale grocery store’s deli section. Same chairs and tables and general set up as a college campus, only the food’s a little more expensive.
Obviously a lot of college moms love this brave new world where they never have to give up the mentality and practices of their college years once they graduate. But it’s driving women who don’t want to live such a tightly structured life just to be moms away from motherhood entirely.
Liberals are in a bind, too, but progressive views don’t include a substantial pro-family ideological component, so the fertility shredding effects of motherhood turning more and more into the world’s longest advanced college degree don’t affect their group norms the same way. Conservatives, though, do have that pro-family ideological aspect and if they don’t figure out how to baby factory some other way, then in the long run there will be a small, extremely rigid hard core having the same 2-4 kids, and this raises wider social questions about how we can ever hope to have normal sex roles when those people are completely pushed out of the reproductive race.