Some stay at regionals because it is closer to home, or they have the seniority to bid well, or they are 45 or so and don't want to start over again. There are LOTS of reasons they stay, some better than others. I know a guy who, when AWAC was bought by United a number of years ago was a captain on the 146. He was offered an interview at United and didn't get the job (only 1 AWAC pilot did IIRC) but others did because of United's system of preferential hiring at the time.

He is a lifer now. Bids well and is about 48 years old and doesn't want to commute across the country to a reserve spot.

I have said before that if so-called 'regional' jets were capped at 50 seats I would support that 100%. I think most pilots would too, since it might mean getting a seniority number at a legacy or mainline carrier sooner rather than later. But right now that is not the case and the carriers' managements has successfully been able to chip away at the scope clauses. Whose fault is that? Continental has successfully kept it at 50 seats I think. Good for them. They are hiring. Coincidence? I think not.