Because they couldn't beat out Mac despite having the opportunity to do so. Zappe had his shot last year. He crapped the bed when he played in the same game as Mac and he had a chance to steal the job for good. THEY SUCK.
Yeah it's an obsession. Zappe nor Mac nor any of these clowns should be part of the equation next year. It's just desperate fans hoping there is some magic on the bench. It's irrelevant at this point and shows that our fanbase is still looking for some saving grace because they can't accept how fundamentally broken this team is.
Here's reality, of the 4 QB's on the roster, 3 should be cut. We draft a rookie and pick up an old vet. Either the rookie starts. If the rookie isn't ready and they think he needs time to marinate, you either start the vet or the holdover who we kept for a few games until the rookie is ready. Either way, that holdover should be on borrowed time regardless.
The fact that you are saying we need to "see" and someone "deserves a chance" is pretty telling that you are grasping on to straws. If one of these four guys is our top QB going into next year, then the franchise should be blown up. That's just the long and short of it.