@ The Foss, we are doing 900 hours a year without bunk time. Some people are well over 1,000 hours block time, over multiple time zones. The rosters are literally killing people.
In answer to the other posters, I stay because I'm on the big bus and the lifestyle is slightly less terrible. If I was on the 777 I would have gone to a European low cost a couple of years ago. I did my time on the 330 and know what the rosters can be like. Also, I've been here over 14 years and am 50+. For my personal circumstances it is worth sticking it out for the few years I have left and then retiring completely. Everybody has different reasons for staying, or (increasingly) going.