Denver gave him a "legit chance." Tebow started 14 games for them and was mediocre. Mark Sanchez, too, made the playoffs. In fact, he made the AFC Championship game twice, in his first two years. Does that make him a good QB? No. He's probably worse than Fitz.
Again, "putting up those kinds of numbers" is a completely invalid point. Should the aforementioned Danny Wuerffel, Jason White, Matt Leinart, etc. be given a second shot? No. They aren't, or weren't, good NFL QBs.
I see no evidence for your argument.