While player salaries should increase over time, the percentage of the salary cap dedicated to the QB position shouldn't.
And why is that?
What is the argument against a QB taking, say, 20% (or even 30%!) of a team's cap, if the other competitive teams are also paying that much for a QB?
We are stuck in a feedback loop, exemplified by this Tua/Love dynamic. Why did Love get paid more than Tua? Because his team won a playoff game.
The choice to put wins and losses on the shoulders of the QB over everyone else means that QB play is considered to be the single most important factor in winning. So why
wouldn't you pay your QB an enormous portion of your team's cap?