Without quibbling facts, my two issues with these ideas:
Nobody is paying or saving 30-40% in state income tax. I don't offer tax advice or legal opinions, but it seems that for high earners (the people we are talking about) you'd see effective income tax rates (before accounting wizardry) in these ranges:
Montreal: 58% (33% Canada, 25% Quebec)
Vancouver 53% (33% Canada, 20% BC)
Los Angeles: 50% (37% USA, 13% CA)
Calgary: 48% (33% Canada, 15% Alberta)
New York: 48% (37% USA, 11% NY)
Massachussets: 46% (37%, 9% MA)
Florida, Texas: 37% (37% USA, 0% state)
But they're not irrelevant; just because they aren't as easy to measure doesn't mean they're irrelevant. And just because Marchand talks about the impact of this (when has he ever not talked?) doesn't mean every player feels the same. My most basic argument is that the state-income tax discussion puts too much emphasis on a small matter that carries a lot less impact than people suggest.