At the time that Rashad fought Bisping, Evans was in nobody's title picture - even with his undefeated record. So, that was a matchup of two guys on the second level - exactly where Bisping likes his opponents to be.
I believe that Bisping wants the title but wants no part of someone like Anderson Silva. If someone else had the belt, I'm willing to bet he'd be asking for a title shot. IMO, both he and the UFC have been willing to put him up against second level guys for as long as they could get away with it, milking his popularity while they build UFC in Britain as they play a waiting game for the "right" title opportunity. Should Silva retire, decide to change weights and drop the middleweight belt, or get beat, Bisping will get a shot at a more winnable title fight. If Cote somehow pulls a Matt Serra and takes the strap, I'd bet that Bisping would get a shot at him for the title without needing a couple more fights first (and they'd have time to give him that fight before going through the TUF9 season taping, etc., leading up to his Hendo/Franklin match after TUF9 airs, which would then potentially become a title fight).