It's not so much that stadiums are placed out in the middle of nowhere because of tailgating. It's because they're in the middle of nowhere that people tailgate. They're in the middle of nowhere because land values are usually super cheap out there, and there's a need for huge swaths of parking because anywhere from 60-80000 people (well 100k+ with the new Cowboys Stadium) attend the games. Most US cities don't have great transit systems, and the ones that do (like New York) don't really have the space for downtown football stadiums.
I don't think you need the stadium to be in the middle of nowhere, especially in Toronto where drinking in public is illegal. So the whole tailgating experience might not matter here. It might just mean that any potential team will have to find a creative means of making the gameday experience as good as their American counterparts. Personally, I'd hope the police/government would be relaxed about public drinking, as they are at BMO when some people tailgate pre- and post game. Then just close off the streets around the stadium on gameday and make it a large type of beer garden.
And the reason people bring big trucks is because they need someway to transport the BBQs and whatever else they want to bring. A lot of people bring RVs too. I've been tailgating in Buffalo and a couple BBQs in a park wouldn't be enough to satisfy people. Literally everyone brings some sort of grill and you'd be surprised by the creative contraptions you see (think removed trunks of cars acting as grills...)