At this point, not playing a battletech campaign is better use of your time than playing a campaign with me as a GM having to make so many decisions for you.
idea weenie's post, whle amusing, is an example of not what to do; you shouldn't try to to handle an out-of-game problem in-game. (Seriously, that is an example of how
not to go about things, as was the advice given on every roleplaying board thread I've ever read on problem players. Maybe only as
very last resort if you've tried talking out-of-character and for some reason you can't boot them out of the group unless you "pursuade" them to quit of their own accord, which seems like a fairly unlikely confluence of events. But even then, you'd be better just saying "okay, then," and ignore them for the rest of the session.)
But yes, ultimately, if a player decides that rather than play the game that is happening, they refuse and basically sulk ("I sell my mech and retire"), then YES, they (and everyone else in the group) would be better off if they didn't play.
At the end of the day, you've basically been creating this hypothetical straw obstreporous player that, as they are only a hypothetical and not a real, actual person, cannot be dealt with. Especially since the ultimate answer to a player who doesn't want to play the game the GM is running really boils down to a) to NOT play that game or b) suck it up, adjust their expectations and play the game that everyone else is playing. You can't make someome play a game they have decided they don't want to and it is silly to try, as it just makes in not fun for anyone else.
(And in my PERSONAL experience, GMs are so thin on the ground because no-one ever has any time anymore (which is why I am DM Forever Now), that any players keen enough to want to turn up every week tend not to be that fussy about what they play as long as the game isn't intolerable. In my group, I'll admit
I'm probably the fussiest, to a degree, since there's stuff that I'm not keen on - western RPGs, for one, and I made a sporting effort as far as I could, because it was at least a break from DMing. (Something I won't get to do again, since the chap that ran that died last year.))