> Children are (generally?) considered to have some moral obligation to help out their elderly parents (in my family at least), but no legal one.

The level of this is very culture-specific, with a gamut spanning from "children have no responsibility for their parents once they're independent" to "of course the first destination to send cash once you've made it is your folks". The two cultures I've lived among (German and Korean) are very different in this regard.

My personal take is that you should only have children if it's something you actually want to do and consider its own reward, with no expectations on "ROI".

The policy question of whether this is also the correct society-wide social contract to adopt is very valid, though.

If you look at real life reality though -- the argument for stuff like public schooling almost always a dominating piece is "we will educate the kids so society can get a good ROI." That not only the kids are better off, but the people around them will be too. Sure it's nice that the kid gets something out of it, but public schooling would not get as much support as it does were it not for what society gets out of it.

Society never actually holds themselves to the moral standards they demand upon parents. But people are people, people respond to incentives, and individual parents are no different than society in this regard. The position now, and the mass rejection of parenthood, I think in part reflects the outcome of this hypocrisy and doublespeak.

There is case law which establishes a legal precedent obligating (usually divorced) parents to provide tuition for post-secondary education. I’m not aware of any such case law obligating a child to care for his aging parents.

In Canada you cannot get subsidized student loans if your parents’ income is too high. You can’t get student loans at all unless they co-sign. If they don’t want to pay and you want to go to school you have to cut off communication and convince a judge you have no relationship.