Doing a conversion of USD to equivalent CAD is not reasonable. Salaries are generally higher, dollar for dollar in the USD.
You're also ignoring the multiple tax breaks available in the US that aren't an option in Canada: mortgage interest deduction, uncapped 401K contribution, etc.
Median family income in California: $70,187 USD
Median family income in Saskatchewan: $86,970 CAD ($69,516.86 USD)
The currency conversion seems pretty reasonable. And yes, I'm ignoring the various tax breaks available on both sides, as well as a number of other perks (e.g. 55% paid maternity/paternity leave for 35 weeks). We're in the same ballpark here though.
You're also ignoring the multiple tax breaks available in the US that aren't an option in Canada: mortgage interest deduction, uncapped 401K contribution, etc.