Even Steve Jobs said that having kids was more fulfilling than starting companies and creating products. If you're a startup founder, there's a few ways you can go. You can spend a few years working very hard in the hopes that you get rich. Then you have financial independence, which solves a lot of problems and allows you to focus on doing fulfilling but less lucrative things with your life. If you're not going for a huge liquidity event, you can spend a few years working very hard in the hopes that you can create a successful and sustainable business which, hopefully, you can happily spend a good long time working at in a role you created to suit your own skills and interests, like "CEO".
There are always exceptions, and there's a romantic appeal to figures like Erdos, but it's a huge disservice and a huge sense of entitlement to expect a career, of all things, to take a central place in a happy and balanced life.
This is something that even I have observed, in some cases I have even seen when people take it like "only startup = happiness".