I think that, especially with the benefit of hindsight, you can see that Marrone did a pretty good job overall in Buffalo. I can't imagine Jacksonville was going to find someone better than him who would actually take that job. Everybody's going to talk about Blake Bortles -- and he's bad -- but that team in that division can survive and win with him until they can find someone better.
I don't necessarily view these jobs as a question of who the quarterback is, but what the ownership, GM, and overall talent level of the team look like. The division the team plays in has to factor in as well, which makes that Rams job a lot less appealing than it could be.
The Bills actually look like the team that has the best pieces outside of the Broncos, but then there is the bad ownership situation, the bad front office situation, and the fact that it's Buffalo. That they're zeroed in on a guy who has been passed over in every hiring cycle for what seems like 15 years tells you everything, I think. #1 qualification for that job is that you have to be willing to accept it.