We also offer significant advantages that the majority of the league cannot match. However unlike the Lightning/Panthers, we don't seem to benefit from that at all via getting better contracts.
One is
endorsements. Tavares made 1.7M in endorsements, Marner 2M in endorsements, and Matthews 2.3M in endorsements, compared to Karlsson, Panarin, Seguin, Price, etc all making $500K or less in endorsements. Only McDavid, Crosby, and Ovechkin make more in endorsements.
Another is the signing bonuses. Marner gets something like ~41M out of 61M paid before the season starts in the 3rd year of his contract (i.e. when he's played ~33% of the contract, he's already been paid ~66% of the contract). This is significant value, because he can invest that earlier and make millions of extra dollars off of it. Players
want this from the teams. In the give and take of a negotiation, this should lead to longer term deals and/or lower caphits. Instead, we just seem to give absolutely everything (NMC, deals that take players right to or just past free agency, very high caphits, maximizing early signing bonuses, etc) while providing a unique environment to make an extra several million in endorsements that wouldn't be available in other marks while getting nothing in return.
On top of all of that, it's not even like the tax advantageous teams are the only ones getting better deals. Pastrnak, Gaudreau, Aho, Scheifele, Ehlers, Konecny, Provorov, Larkin, MacKinnon, etc aren't playing in super low tax jurisdictions.