Over 70% of children in America were raised in two parent families in 1997. That percentage is virtually unchanged today in 2019. The difference, and it is not unmeaningful, is that cohabitation went from 3% to 7% in that span of time. Married parenthood dropped slightly from 68% to 65%. This suggests that at the margin, marriage was too costly, but the importance of keeping two parents around was high enough that it produced a cohabitation increase rather than a single parenthood increase.
Single parenthood didn’t budge. It was 25% combined for single mothers/fathers in 1997 and it’s the same two decades later.
It’s also worth noting that single parenthood was 13% in 1968, while married parenthood was 85%. Kids being raised with no parents varied from 2-4% over the decades, currently at about 3%.