There will always be the Catholic faith. With all due respect, the conclusions you arrived at after observing the attitudes expressed by your grandkids, and other young people, are not necessarily the same for many of us.  My observations differ from yours, possibly because of the type of Catholic parish church I attend. Since our parish has a school which requires that all grades attend Mass with their respective classes, of course I'm going to see a large number of young people every week at Mass. However, I see a large enough number of young adults at Mass who are beyond parental control, to make me believe that they are there because they want to be. I'd say based on my observances, that the example of dedicated, orthodox parents and teachers, will pay off in faithful Catholic adults.