I bet (hope) there's going to be a cabal of teams (and NHLPA members) pushing for tax relief of some form on the salary cap in the next CBA. The Leafs' cap in function is considerably smaller than teams like Tampa and Dallas.
Leafs advantage is big market team with endless money and the ability to front load and payout signing bonuses and structure contracts to their own and players liking. Small market teams, budget teams and non traditional hockey markets have to use other tools like state tax breaks to their advantage to lure and sign players.
The downside of being rich like Toronto is that players that want to sign deals with Leafs like Marner, Matthews, Tavares etc know Leafs have the ability to pay more than other markets and have a real desire to freely spend in hopes of winning..
That is why Leafs players and their agents don't use market comparable players of small market teams or tax break states as their comparables, they simply use the Toronto market and Leafs depth chart and where they see their player ranking and getting paid accordingly. JT signing set the Leafs market at $11 mil now Auston argued and won and said I'm better and younger and deserve more than Johnny, and now Mitch is up and he too is using his teammates and where he fits on the depth chart as his negotiating position.
It wouldn't even likely matter if the NHL CBA tax adjusted the Toronto market, the players would still ask for top $$, and if it wasn't tax breaks they would simply argue cost of living is higher in TO than TB or Dallas. Try and buy a similar house in TO, TB or Dallas and you would see what I mean.
ie If Marner took the Kucherov deal, and the CBA adjusted for taxes for players that both took home identical net pay, then Mitch buying his house in Toronto for $1 mil and Kucherov getting the same home for $500k in TB, would say he needs more take home money to offset that, and so on and so forth ..