Some stay with the smaller operators because of location, ie Regional Areas. I know a CFI who has held the same job for the last few decades. They don’t have mega mortgages or traffic to deal with. But they love their job. They only get 60 grand a year.
Here’s a tip, don’t go into Aviation soon as school ends. Get a job in a trade, IT, medical, whatever, just not Aviation. For the next decade set yourself up, buy the nice car, the investment property, build savings, and even hold a Private license as a hobby. Save for the CPL. This is what I did. My first paid flying job came mid 30s. I also found I progressed quicker than others. I’m not sure if it was age or life experience.