USD v.s. CAD doesn't mean shit. It's not like something that costs $3CAD in Canada always costs $3USD in the US. All else equal, if USD -> CAD is a rate of 1.3, then your $3USD purchase in US would just be $3.9CAD in Canada.
The conversation about buying power between US and Canada is not about exchange rate, it's about cost of living, and I'd wager on average the cost of living where Canadian teams are located on average is greater than the cost of living where US teams are located. And that is in addition to generally having higher taxes.
Lol. Adam Smith, is that you?? "All else equal" in economics always made me laugh in University. All else is never equal, and only qualifies for base theory exams where you look at charts in a vacuum.
In 2019, the PPP (purchasing power parity) for CAD to USD was 1.194, per OECD.org. Per the Bank of Canada, the annual average FX was 1.3269. PPP "theory" compares currencies through their ability to buy certain goods or baskets of goods, which is what youre talking about. Your example of 3US for a cheeseburger or whatever, to 3.9CAD, is of two currencies at par PPP assuming a 1.3 FX rate.
This almost never happens, since currencies are based on supply and demand, along total market sentiment. Added to the fact that the US is always in demand since it the most used reserve currency, means having or earning USD is generally beneficial.
PPP theory is macroeconomic and more about GDP and trade. Its fairly useless when comparing Ohio to Alberta, etc. Its absolutely an advantage to make USD in Canada. Maybe that advantage is lessened if you live in Vancouver, but to just say purchasing power = FX rate, is ultra simplified.