And at the end of the day most of the games will be played in the US anyway, so I'm not sure why Canada and Mexico wanted to be there. Maybe Canada wanted to finally be able to host it, but the other two already have done so in the past.
I think that when it is hosted in a single country is better but usually FIFA has done so when the host country has some other countries near it that love football also,I remember in 2002 this was the case and the World Cup was held in Japan and South Korea and it had a lot of contention because of the referees favoring the host countries in a clamorous way,Italy lost 3-0 to South Korea something which was unimaginable until then.That is why I am more in favor when a single country is hosting the World Cup rather than holding it with other partners which can bring us to this non grateful situations where big teams are out of the play because of referees favoring home countries,it is much better when it is just one home country.