The amount you pay will depend on where you live, if you live in New York then you need to add 8.875% in combined taxes. You, in BC, pay 12% in combined taxes - an additional 3.125% The exchange rate between CND and USD is ~0.79:1.
Of course you might live in a lower tax area but you might live in a higher tax one also. Either way there it's not going to add up to a $400 difference. Unless you count CND and USD at the same value which they are not even close to being.
I have to pay 23% Tax here in Ireland on goods. The XF 56mm is €999 inc Tax here (€812 without). So I have the best value off all three if you are counting currencies on par that is - oh lucky me.
Also, you can't make direct comparisons unless tax in each country is used in exactly the same way. Spending power may be higher in the US, but they also have to pay health insurance, high interest student loans etc. Here in the UK, yes we have 20% VAT, but I could live in hospital and not build up crazy debt.
In my case, I just wait until I visit my in-laws in Oregon, USA where there's no sales tax