Parents are a huge part of the issue.
I think public schools and forced socialization of children in those environments contribute as well.
In school you have to deal with and interact with people your parents would normally never let you get near.
I have seen some fantastic parents. Just this weekend on an all-day train trip, I saw these two parents - particularly the mom - who handled their children incredibly well, and reminded them constantly about politeness, attitude and behavior. I wish all parents cared so much to take the time. Time and effort can be critical.
I believe that parents should plan to have children and plan to make them the absolute highest priority - period. None of these “nights out with the boys” or “girls night out” drinking with your buds, letting the children be baby sat. Or focusing more on making money than raising their children. Priorities all screwed up.
If people are not ready to be fully committed parents, they should wait to have children until they are.