Its not solely about whether you could fill stadiums, its about the size of those stadiums. Even BC Place is what, 54k? CONCACAF knows they can sell out an 85-100k+ US stadium for matches involving Mexico without even needing traveling fans. Its all about money.Canada could and would fill stadiums as well. We might not have the population, but the game is really growing here.
The real shame is we’ll never see an “America’s Cup” kind of tournament with South and North America more like the Euros. That would be great, but these bureaucrats would never let anyone else host it.
I don't think there's any interest on the CONMEBOL side to involving NA nations. Would be good. We'd all struggle to get out of the groups though.