Manning in his decline is better than Tebow was in his prime.
Manning cost the Broncos 90+ million, Tebow 1.5 million.
Of course a veteran quarterback with many years of experience is going to have a better skill set. Tebow, fresh out of college will have to learn and adapt to the NFL. One season is not enough time to make that happen.
Is Manning a better quarterback? I will give you that. Is he 80+ million better .... based on his performance, not.