The general gist of your post is good, but this opening statement in misleading/wrong on several levels. First, entire countries don't support a league - a number of cities in a country do. (And owners are more important that the local population is, but if we're arguing about population then we'll overlook that point for now.) The fact that NWSL only had 9 teams up to this point is irrelevant - we don't know how big NWSL could eventually get. The important thing is that NWSL has shown that markets as small as SLC and the Research Triangle can work, (while Rochester appears like it was not enough,) so the best comparison that could be made with that data is looking at how many Canadian markets there are of that population or more, in which case Canada does have enough cities to support 3-4 NWSL teams (6, actually). Also, Louisville is not in last place, Kansas City is.