It is ASTONISHING how often this needs to be pointed out to people, and then still trot out the old line of "the union won't let them sign that deal".
But it's wrong.
That's not how a free market works. the amount of money available is not what not drives these negotiations and it's a fallacy to believe that if a player takes a million dollars less, it now leaves a million dollars for someone else. what it actually does is take a million dollars out the pocket of a comparable player because the market has shifted. That's why the Union and the player agents convince their players to max out if possible.
It no different than the real estate market. What is a house worth? it's worth whatever someone will pay for it, and any subsequent comparable house is now worth the same, and the owner can ask a similar price to sell it. How much money the buyer has is irrelevant.
the only time true "discounts" can actually be a thing without messing with market is the truly elite players who don't have legitimate comparables since an agent can't use them to compare their clients to.
Look at what Seth Jones did to Edmonton's cap space, he became the comparable Nurses's agent used to leverage a massive overpay, and the market has since corrected. But the Oilers are still stuck with that.
The salary cap does not matter, a player is worth whatever a team is willing to pay, which will always cause market chaos.