I laid it out perfectly for you. You just refuse to see it. You admit that there is not another coach in the history of the NFL that had as much talent as Levy and still failed to win the SB. That is all that needs to be said. You can compare the records of Levy and Wanny all you want, but you cannot escape the fact that Levy had more talent to work with and still FAILED.
The measure of a coach is what he does with the talent he has and Levy set the standard for doing less with more. There is no excuse for the zero SB titles from that team. He was handed a team loaded with talent. They were extremely fortunate with injuries. Kelly, Reed, Thomas, Lofton, Smith, Talley, etc, etc all stayed relatively healthy during the SB runs. In all of the SBs they were outcoached.
That is the sad legacy of the Bills. The best they were ever going to be turned out to be not good enough.