I am not saying that the NHL is necessarily wrong in doing this. But if you are going to enforce parity by an equal cap. Equalize cap hit based on taxes.
Which sounds easy enough, right? Except when you say "equal cap" and "taxes" you are implicitly saying
all taxes, and once you narrow it down to
well, I only mean income taxes you're admitting you don't
really want it to be equal, you just want the
appearance of it being equal.
Let me give a practical example of why this could be problematic, though: say the baseline cap is $100 million and then teams get "extra" based on income taxes. Let's make this
really simplistic and say we're only counting state taxes, and the "extra" any team gets is 100 / (1-x) where x = the state tax rate (in percent). Nashville, Dallas, Tampa, Florida and Seattle - all in states where there's no income tax - have a cap of $100 million; Chicago (where the income tax is 4.95%) has a cap of $105.2 million to spend.
Illinois suddenly repeals its income tax, and Chicago has allocated $104 million to player salaries for the next season. The Blackhawks now have to cut $4 million to get under the new cap of $100 million - which, because contracts are guaranteed, they can't unilaterally cut $4 million, which means they have to trade out $4 million in contracts. Or, failing that, they have to buy out players to get under; buyouts count against the cap, and to cut $4 million they really need to cut 3x that (assuming 2/3rds cost) to get the 1/3rd cap savings ... meaning they have to cut like $12 million to get under ($12M x 2/3 = 8M, which now saves $4M that gets them under). But, that's $8M they have to carry in dead cap space for however long.
Maybe state income tax rates don't change that often ... but they do change - and it would be unfair to suddenly penalize teams for actions out of their control. Then layer on other taxes that have to be considered (sales tax, property tax, personal property tax) and the fact that the
professional athlete jock tax imposed by some places has a very non-negligible impact as has been demonstrated repeatedly.
Oh, and there's an entire escrow side of this - right now, everyone shares the burden equally; if teams have different caps,
shouldn't players on teams with higher caps [who are more likely to drive spending over the 50/50 split point] pay more of the escrow burden? If players are traded, that's an entire set of math calculations that have to be carried for every player; who's tracking all of that?
I'm going to repeat what I've said before: if
no state income tax was such a boon for sports franchises in those states,
why aren't franchises in those states overwhelmingly more successful? They're not. Teams in "no income tax" states aren't winning titles, aren't highly competitive, because they're constantly attracting players who want to pay no income tax, and they're certainly not winning a disproportionate amount of titles or even regular season games, division titles, whatever with that alleged advantage. This "massive advantage" is grossly overblown, even in sports where a salary cap has existed for years and players should have figured out how to maximize their income within it.