You seem to have a very limited definition of civilization. Nuclear families are one way to create a civilization, but far from the only one. Families can look very different from that model and still work, raising children who are happy, healthy and productive members of society. This has always been the case, in fact, throughout human history. Many civilizations use the "it takes a village" approach to raising children, and it works too.
No matter what families look like, civilization will continue to exist. It might look different than it used to, but that's always been the case. Even the so-designated "nuclear family" looks different today than it did in the 1950s, the 1850s, or the 1050s.
-- A2SG, change ain't scary, it's inevitable.....