I'll stick up for Joey here... He likes what he does. Day turns, multi leg, whatever, in a narrow body with some intl flying to Caribbean and Central America. If he doesn't get bored from that in 30 years that means he chose wisely.
Others have a desire to try out new things. But let's get to the bottom line. Why is wide body flying so senior? Pay & QOL. Most days off, least amount of work. Period. If I could do that in a 737 or a320, guess what, I'd bid narrow body. Trust me on this, I fly cargo in a 747-400 and have had to fly 4 legs in one day in it, but I had a 2nd capt to do the other half of the work while I slept. It sucks no doubt, but what we're getting at is at AA you'll be sleeping in your bed more, and risking your life a lot less.