If you want to write new code and have a lot of influence over the overall implementation instead of fixing bugs on a years old steaming pile of tech debt.
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.
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.