Effective tax rates provide a clearer picture. Let's take one example.
I plugged in $200k (CAD 270k, admittedly quite high for Ontario) of income to a California[1] and Ontario[2] tax calculator.
For California, I used the following: "Filing status - Single, 401k deductions - $19k". Effective tax rate: 30%.
For Ontario, I assumed CAD 26.5k in RRSP deductions. Effective tax rate: 35%.
> cost of real estate/rent in Toronto or Vancouver is not significantly cheaper than SF
Buying isn't cheaper. Renting is still significantly cheaper (at least by 1/3).
> salaries are lower
This is true.
> cost of living expenses...are higher
Cellphones and internet, yes. Everything else (yes, even milk and dairy products if you shop at Costco) is comparable to US prices.
> you're still going to want to carry supplemental health insurance
Most employers provide this. And vision/dental is far cheaper than paying for everything.
I'm not saying you'll end up with more money if you live in Canada. I just want to point out that many of the fears of "higher taxes" and "higher CoL" may be a bit overblown.