Yes that part is very easy. I can’t understand why someone would choose to give up their prime years for a child. The entire idea of retirement is a direct consequence of this. You don’t need to retire if you can you know, just continuously enjoy your life the entire time.
I think there's a direct comparison to be made with the choice to devote one's "prime years" to building a startup. It's a meaningful project that materially impacts the world in a way that one has a decent degree of control over. And it can be fun, even in the same moments it is deeply difficult!
Not really because you can just walk away from a failing startup. A startup can also profit, or you can hire people to take responsibility away from you, or even sell the startup. A child to me is more akin to a jail sentence in that you can’t escape without getting in even more trouble.