No sympathy. Pilot's who willingly choose to fly for the regionals get what they deserve. You know what it is going in. I agree, pay is atrocious, but until pilots value themselves better, why should the airlines. There's no shortage of pilots who will eagerly jump at the chance to fly a fancy jet. Remember, the flying public could care less how much you get paid so long as they get to fly for cheap. I don't mean to sound harsh, but with so many horror stories about QOL and pay, you have only yourself to blame.
Why should they expect more pay? They have no experience. Flying a 121 jet aircraft should be reserved for those holding ATP's. It doesn't say Captain Transport Pilot... It says Airline Transport Pilot.
When the entry level experience level changes, I'm sure pay will too. There will be some bump up for pilot shortage, but in most cases reducing frequency and increasing capacity will cover the shortage short term.
However, by then the ATA will sell the idea of MPL to congress and pay will tank again.