There's no salary cap on Hollywood...
Honestly, I don't care how much anyone gets paid. I care what percentage of the cap they take.
Garoppolo is reportedly a little more than 20% of the 9ers cap next year. Now its heavily front-loaded, because that's the situation they're in, nobody can sustain tgat and build a team. 15% is what his deal averages (against projected 2018 cap) and that's a highwater mark to me. In my eyes, to eat up 15% or more of your teams cap, you've got to be the reason they're winning games. It's not too hard to argue that in 2017, he was. We'll see going forward - that puts you squarely in Top Ten category I think.
If you're a role player/game manager, a 'with a running game and a great D we can win with this guy' I think you can't eat that much cap. I think Cousins is somewhere in between a Top Ten guy and a role player - closer to a Top Ten, but I don't think he'll ever get there. If a team pays cousin's close to 20% of their cap, I think they're in trouble.
Unfortunately, the QB market is what it is. That's not going to change for the better. QB salaries will continue to rise. Fortunatly, the cap also continues to rise each year, 15-20% of this years cap will be less in each year to follow.
Time will tell what Garoppalo is. He had a great run of 5 games but has not proven anything yet. Cousin's is a top 10 QB and will be paid slightly more than Garappalo. I think the Eagles proved you can win in today's NFL with a good , not great QB.
That being said, next year's QBs will be paid more than cousins and it will continue. That's what makes draft picks so essential. You have to draft well to get production from your young players in their first contract. Drafting players to develop is a killer. If they miss you wasted a pick, if they hit, you wasted the value years and will be due big pay days after only giving a short time at good value.