For me it's just a matter of "comfort zone".
I've been flying for almost 30 years. I have command time from the airforce. Where I am now I have been pushed down on the seniority list by my present colleagues after a "merger".
No promotion in view yet and frankly, I don't care about it. FO on longhaul suits me perfect. My body has converted from speed to comfort. Running between aircraft, de-icing, SLOT's and 3 CATIII per day is not my bag anymore.
I have a good salary and a good life. The day I retire I get the same pension as those who are CDR's. My allowance is better so in the end it's not much of a difference there either.
Why should I change? It's better being late once a day than five times a day.
Rgds
PS Old Smokey; For me, they can excercise their command as much as they want but if they screw up, I'm not the one that will sit to the right with my armes crossed. Command is one thing, survival another.