I've seen several cases where parents were fiscally responsible but also wanted to give their kids opportunities they did not have. This often means the kids are raised around other wealthy families. They interact with them in neighborhoods, schools, sports, vacations, etc...

Anecdotally one thing I've seen is this: the children of fiscally responsible parents grew up driving 10 year old cars at a high school where lots of other kids drive very nice new cars. They grew up around kids who have the latest iPhone and they do not. And the net effect on the kids is that they decide that when they get older they are not going to live with the same austerity as their parents.