Sometimes the issue is quality of life. It can be very sweet at a regional with seniority. My neighbor has seniority at a regional.
He is home most nights, gets most of the important holidays off and has the pick of the bids. Granted, he only pulls in maybe 75-85k a year as a pilot, but in his off hours he is a real estate developer. I would venture to say that his real estate income is triple his flying income. Plus, with the time off, he uses it to do a lot of traveling.
For some people the flying is not the end result. It's a fun thing to get paid to do. I've done well on my investments but not well enough to rent an Airbus A320 for the 80 or so hours a month that I would like to fly. Until then, my employer can foot the bill.
my 2 cents...