I am happily married - largely driven by personal values religiously influenced moral principle. For most my friends, the question they pose is what is the benefit of marriage? You tie yourself down to monogamy, give up your personal life and risk losing half of it plus a life of child support and alimony in a divorce.
I don’t have an answer but I think the root cause may be different than increasing access to child care (which certainly helps) on the margin.
Edit for another random anecdote: almost all my Jewish friends in their mid 30s who are well to do are married. Can’t think of one that isn’t. I believe there are cultural correlations that can be drawn.