While this might be true, and the argument can definitely be made, there is also the fact right now that arguably the best 3 players in the league right now in Connor McDavid, Leon Draisaitl and Auston Matthews are all on Canadian teams, and neither team can still make it to the Stanley Cup finals.
The last time a Canadian team won, was the Montreal Canadiens in 1993, and they are actually the last Canadian team to make it to the finals again, when they lost to the Tampa Bay Lightning in 2021.
Unless you've been drafted by one of the Canadian teams, many players seem to stay away from the Canadian markets due to the high tax. Why lose half your paycheque to taxes when you can play on a team like Vegas and keep your whole paycheque?
Canadian teams having been pushing to become legit cup contenders for a few years now, especially with the emergence of McDavid and Matthews in these markets, but they've never been able to quite pull teams together and acquire the right players to become truly elite.