The tax rate difference is overblown. Has a player ever said that a major reason he chose a team was because of it? Have we seen players flock to Florida,Tampa,Nashville,Dallas, and Vegas before? We have not but we've seen big FA choose Toronto (Tavares), New York (Richards), San Jose (Karlsson) and those are some of the highest tax brackets around.
Additionally the difference is not even as much as it appears. According to capfriendly a 10M Salary would be worth 6.3M in Florida and 5.1M in NY. However this is not strictly true. They consider it as all 82 games are taxes at one rate and not 41 at the home rate and 41 at varying road rates. If we assume the road rate for all teams is the average US rate of NHL teams (6.6% and this is not totally true as of course the Metropolitan Division is a bit higher than the Atlantic but works for ease) Now that 10M salary is worth 6.1 in Florida and 5.4 in NY. When you account for escrow and such the difference is even less than that. It's not negligible but it's nowhere near this huge difference it's made out to be.