there's a lot more to this decision than just "Mark gives us the best chance to win." <- whether Rex truly believes that statement, it's IRRELEVANT.
Right now (& for at least 2 more years) The Jets are STUCK with Sanchez on the roster. They can't just bench him and say "we F'ed that draft pick up" and also say "This dude can't play in the NFL- we were wrong" and ALSO say "We now know he's worth NOTHING, so why even play him."
What's happening here is:
1) Can Mark Sanchez grow a pair of balls and ANSWER BACK to his benching? or will he fail miserably and have shattered confidence?
2) An 'Audition' for other teams seeking a QB still exists because the Jets have 'clearly' not lost faith in their starting QB.
3) If McElroy got the start and threw 3 INTs in the first half- things would just get worse (same for Tebow).
4) I think they want to play Tebow this week (as the wildcat) -- They don't want to be pulling McElroy for Tebow just yet.
there's a lot more to this decision than just "Mark gives us the best chance to win."
That's all there is to it.
Of course, you didn't list any of the real issues here because the Front Office and owner of the Jets likes to pretend we're all naive fools:
1) This is not Rex's decision. McElroy's profile as a game manager is exactly all of what Rex has ever wanted from his QB.
2) Sanchez has plateaued and now regressed. He is not going to get better. Thereby, saying he gives you the best chance to win is a blatant lie because if he has reached the point of being bad enough for you to pull him in a prior game then you are making a choice in one of two ways:
A) You aren't making it at all and it's being forced upon you.
B) You are making it based on personal feeling and emotions.
Having read the book on Rex, it's definitely A.
3) The GM is in a tenuous job situation and your chance at the playoffs is entirely marginal at best. You are caving to the GM's demands and naming the guy he is essentially glued to (career-wise) as your starter.
4) The team is glued to him next year financially.
5) They are on the road and don't have to fear more hatred towards Sanchez.
In essence both the long-term situation with this team (which would entail starting either McElroy or even Tebow since they are relative unknowns compared to Sanchez and could actually improve) and the present are being sacrificed in the name of a GM's job and an owner's investment (that is well-established as a bad one.)
The limited crowd who attended the game on Sunday against AZ went nuts for McElroy. Who can do absolutely no wrong right now. Nor could Tebow.
It's that simple. Both other QB's would provide indication that somebody in the Jets front office has a clue.