I remember an Air Crash Investigation where the investigators were surprised to hear that the two pilots sounded completely drunk on the black box. It wasn't alcohol, it was the lack of sleep – the guys had just flown halfway across the USA on a jump seat to start their shift in NYC and slept in an 8-bunk-bed subrental in a suburb.

So, yes, pilot's low wages in USA's regional airlines is an endemic problem that has killed hundreds of passengers.