Increasing cap holds shouldn't affect a team's ability to keep their own players, just their ability to also carve out cap space. Heck, the Spurs took advantage of this themselves with Kawhi's cap hold.
On a side note, I wonder if the league will address the after-tax inequality in salaries due to state income taxes. The league could offer to pay states a percentage of BRI that roughly equals (or slightly exceeds, to get them to agree) the states' current tax take in exchange for them not taxing NBA players' income. Until I had seen that Durant could get $129M after tax with the Spurs or Heat but only $109M with the Warriors, I hadn't realized that the difference was that big.