I assume when you said that if Salt Lake City had an NHL (and MLB) team like they have an MLS team then "the debate would cease" that your argument is generalized and not specific to Utah. Well, Atlanta evidently had two NHL teams that failed. Their new MLS team, Atlanta United, has like 37,000 season ticket holders, average over 45,000 per game and occasionally will draw in excess of 70,000. If we were to apply your Utah hypothetical to the real scenario in Atlanta the debate would indeed cease, but with an outcome much different than you assert.

Also, do you really think that an NHL team would do better than the Timbers FC in Portland, who sell out their 21,000 seat stadium every game and have a season ticket waiting list of over 13,000?

And I am not even arguing MLS is more popular or "bigger " than the NHL. As Chilango explained, soccer in the US is MUCH more than MLS. The TV viewership numbers for the EPL in the US are generally nearly three times that of the MLS. Liga MX much more than even the EPL. Then there is LA Liga, Bundesliga, other domestic leagues, the Champions League, Copa America, European Championship, World Cup (mens and women's - remember the last women's WC final drew a considerably higher TV viewership raring than the Stanly cup final. WOMEN'S. ). Anecdotally most soccer people I know in the U.S. look down their nose at that league and won't have anything to do with it (and yet it is still doing pretty well and growing ). The point is soccer in the US is bigger than you think but is fragmented, and to some degree runs off the mainstream.

Furthermore, you say that if you ask people which is their favorite LEAGUE, you can almost assure us that MLS would be last. Again their is the restriction to leagues/MLS instead of measuring the sports themselves. NHL has been around a long time. It is the premier ice hockey league in the world. Currently the 22 year old MLS would be lucky to claim the 10th best soccer league in the world. And then there is this: the Gallup organization essentially did about what you propose - ask people what sport is their favorite. The most recent results showed that soccer is the favorite sport of nearly twice the percentage of people as hockey, and has climbed to within 2 percentage points of baseball. This spawned a Forbes article about how soccer was closing in on baseball. The Gallup poll showed that only 1% of Americans over 55 years old claimed soccer as their favorite sport, but for those between 18 and 34 years old - that valuable target demographic known as "the future" - soccer was tied with basketball for second!

As Chilango explained, your mistake is conflating league with sport. The country is becoming more globalized.

Now, there are aspects of these "American " sports that are more main streamed. But what is main stream but that which is established by any generation's 55+ demographic. Things are a'changin'