I have a friend, meanwhile retired, who made his way from the 737 via DC10 to the A340. Senior First Officer. He was offered to upgrade to left seat and he refused.
Reason: As he had reached to uppermost payscale for F/O on longhaul, and as a "new" captain being forced to join the short / medium range fleet, his salary would not have changed for several years. Since he enjoyed the longhaul destinations and the different lifestyle, it was out of the question for him to alter anything.