Just basing it on a pretty simple fact that players take time to develop. Yes McVay has some time to develop players, I don't know why you would think otherwise. Not to mention, TE's have a much bigger role than your average WR, they have to inline block, block 1 on 1, Pass protect, Run routes and so on. It's usually the reason they take longer to develop.
You're not just arguing with me, you're arguing with John Gruden as well, and I'm going to trust his word over yours mate.
And I think I proved my point by showing you actual facts/stats.