Well, in NORTH America, there are only so many countries in it. It has the big three: Canada, USA, and Mexico. Not to state obvious facts, but these three countries have hosted an Olympic Games so far. The rest of NA consists of nations that need major help in many areas. Hosting the Olympic Games would be pretty much impossible to achieve here.
Well, that said, it doesn't mean that these other nations haven't tried to get a bid for an Olympic Games going. Havana (Cuba) and San Juan (Puerto Rico) tried, but failed to get candidate status in each case.
Also, the cost of hosting just one Olympic Games alone could bankrupt certain nations, if not done properly. The events between winning the bid and actually hosting it almost becomes international news, if things get sensational enough. However, on the flip side, the prestige on the city and country hosting one is huge.