actually, they are. Not gun to the head forced, but social structure forced. Which is a good thing. If hubby’s mom or dad strokes out, hubby is going to want his mom taken care of outside of institutionalization. If a child develops a severe disability, it’s mom who usually stays home.
Or, we could decide that everyone is a worker unit, marriage is irrelevant, nothing is more important than showing up 9-5, and any child or adult with a problem should be institutionalized at the expense of the state (oh the taxes) and forgotten, rather than be a ‘bother’ to the non-existent family unit, which now has no reason at all to remain a unit.
The point is that it is a decision by the person. They are not forced to do it.
I know too many people who hang themselves on the Tree of Woe as if they had no choice.