It has a lot to do with the way they're sent around. A lot of stock, for some strange reason, is manufactured in Asia, then sent to the US and distributed from there. As a result, you've got at least 2 sets of import tax and then the middleman and shipping charges. That shouldn't be as drastic in Canada, but it's stupid considering that Australia is very close to where much of these products are produced, but it still gets sent back and forward.
Publishers are also responsible. They set RRPs that retailers have to deal with, which is not only more, but they often set them when the US exchange rate is much higher. We're at parity with the US dollar, occasionally jumping above, yet we see products at the 50% bump they were from 5 years ago. This is why we see different prices on digital media, such as Steam and iTunes.
Ah well, that's just my rant for the day.
As for what you were saying, exclusivity is a joke and often misleading. Sadly, there's not a lot you can do. :cer_nod: