There really isn't a supply of those guys out there is the problem. It's either rookie deal or expensive guys. What we will probably continue to see though, are the "pay the piper" type deals like Stafford had and Allen is on still this year, where there's a year or two of a big contract with a low cap hit, then it really escalates. Rams are kind of the case. Is easy to look at the Rams, as their go for broke year ended with a SB, but that margin is razor thin. The odds you win a SB even in a stacked year like that is not great, and now they are going to in terrible shape for at least a couple years.
I am very curious to watch the Bills moving forward. Based on cap their roster is going to start looking a lot different. The cap hit from probably their three best players - Allen, Diggs and Milano was like $33M this year, and that goes to $73M next year.
Basically I see the league as the Chiefs and 31 teams that have at best small windows to challenge before the QB cap beast alters their roster. The Chiefs have a QB that's great enough with a cap number that is going to keep them in the hunt as long as he's around and healthy.
Teams like the Eagles, Bengals, Chargers, and others have 1-2 years depending on their QB contract situation. The 49ers are the other oddball, but who the hell knows depending on Purdy's injury.