Can you support this statement at all? You didn't really say anything to reach this conclusion.

I sort of feel like my entire post reached this conclusion even if not explicitly. Which part do you find inconclusive?

I don't think this is an important part of marriage, but let me tell you: people are absolutely shit at having arrangements for stuff like this. They don't want to think about it. They don't want to do it. They don't do it, then something happens. Everybody argues over who has the right to make the decisions, time and money is wasted. People are SUPER shit at this. Only 26% of people actually have one.

This basically says that marriage is a good idea because it is convenient.

If you have supporting evidence of this, I'd love to see it.

I don't have evidence of the effects on adults who see their parents divorce but that is the point. People tend to care less about marriages when they stop affecting children so they are much less about matrimony then they are about providing stability for children. About the only thing this proves is that marriage is conducive to raising children which doesn't explain why it should be a legal institution, nor does it defend child-free marriages.