why would anyone work in startups as early devs anymore. Tell me what is the upside? There seems to be only downsides. Startup Fails , you loose - Gets acquired - you loose What is the motivation to perform .
Not all places with large existing codebases are that bad, but if you are experienced, it can be very personally satisfying doing something well before it has degraded over time.
I have worked in quite a few. One is a household name down here in Australia. I was the first engineer with the two founders. I worked 2 years 24/7 for half the salary I got when I left. I'll never get my money back but that's ok as I loved the time there.