The Maritimes, Alberta and British Columbia might not have followed suit. The Maritimes kind of were forced out by necessity, what with no land border to Canada anymore, but the other two were shockers. Its some miracle that Ontario has managed to keep the remaining Prairie provinces.
That's what you need to fix though to keep Canada united. Pretty much the big complaint has been that the tail wagged the dog, and all too often folks felt like Canada was simply Ontario and buddies.
Would NAFTA have gotten as much off the ground without Canada splintering? I don't see a united Canada accepting the US dollar without all the squabbling over using the Canadian dollar or not. I do wonder if the 52nd state crowd here in the USA trying to seduce Cascadia or Alberta into joining the US will give it a rest though. A common currency and passport in North America alone was an ugly fight, especially with all the bigots whining about Mexico being part of it.