I've been pretty adamant that the Bills would not sign Mario. That even if they threw the money at him he would not want to sign here. I'm not even sure once you crunch the numbers that he would be worth what they were sacrificing to get him.
But when the time came Nix and co. Stepped up big and did all they could to get this guy. If he goes to Buffalo great. If he doesn't then at least we know for sure that the FO is in it to win it.
The OP has it right, you can't blame Nix if people just don't want to play in Buffalo.