I see you glossed over the first part of my post. That's fine.
I'll just assume that you concede that Luck has already engineered a terrific turnaround on a team that lost its franchise (4 time MVP) QB, entire coaching staff, #2 receiver, and a future HOF center.
I also said earlier that I would be shocked if Indy was able to make it to eight wins. Realistically, they're more likely to go 2-6 down the stretch and finish at 7-9. I posted all last year when the team went 1-15. I'm not likely to run away now. Indy's problems down the stretch will be related to their defense. The Colts defense is seriously in the bottom five of the league. Their secondary is just painful to watch, and the front line can't stop anyone from running the ball. They're going to fall behind early, and that's going to mean that Luck is going to have to throw all over the place to try and keep the team in some games. That's going to spell trouble for him down the stretch. Naturally, his numbers are going to fall off toward the end of the season when they play stiffer competition. That's to be expected.
And the ROTY may not even come down to Luck or RG3. Doug Martin has racked up over 500 yards rushing in the past two weeks. He may have even added another TD this morning. If he can keep up this pace, he's literally going to run away with the award.