There is a version where the worse it would be the more rational it becomes to accelerate there faster

1. As a protective measure for your kids. Similar to the motivations for many civil wars
2. If you're going to be miserable, hungry, on the run, etc. you have a better chance of surviving that at the age N than N+10, for all N > 15. Better to start the misery now and adapt while you are younger. You might even get to see the other side for sufficiently small N.