Sorry, but that's not how it works. You can't pretend all players are signing under the same set of circumstances. The cap changes, which means the value of the dollars changes too. At the time Panarin signed, Ovechkin was on a contract that was lower in cap hit, but at the time he signed it the deal was higher relative to the cap than the one Panarin signed (16.82% vs 14.29%). And then you have to factor that Ovechkin contract was signed when the player was RFA and not UFA, which means they were playing in different markets.
Starting the same year as Panarin's deal, Matthews signed a contract that was only slightly less than Panarin... but again, he was an RFA and not a UFA. Once he moved into UFA territory, the deal he signed was a higher percentage of the cap than Panarin's.
Cap hit % isn't perfect, but it's far far FAR better than raw cap hit.
The league didn't shut-down the back-diving contracts by fiat. It was part of the CBA negotiation.
Escrow is a great example. The players wanted a cap on escrow. The league said "fine, we want slower cap growth." And we ended up with a cap on escrow and a new formula for calculating the cap.
Every single thing is a point of negotiation. It doesn't matter how many players benefit from it.