American soccer is not embraced by the public. It is probably the fifth or sixth sport in America. It isn't the talent. The MLS is one of the most improved leagues over the past four years. It has become the best in North America, and it is catching up on the South American leagues. I'm not saying that it is right behind the EPL, La Liga, or Serie A, but it is very good. It isn't the stadiums. They are great. Toyota Park is better than some of the major sports (NFL, MLB, NBA) stadiums that I have been to. It isn't the sport. No matter how people want to twist it, soccer is more exciting than basketball and baseball. A goal in soccer creates a rush that cannot be matched in those sports. A gamewinning goal is more exciting than a walkoff homerun or gamewinning three. It has to be the league.
The teams are always the same. In the Premiership, La Liga, Serie A, SPL, and Bundesliga, teams are moving up and down due to record. For example, the Sunderland, Birmingham City, and Derby County finished in the top 3 in the Championship, the second level on the English pyramid, so they are now in the EPL because of the way they finished. In the SPL, Gretna has replaced Dunfermline because Gretna won the Scottish First Division. I think that if fan bases of the USL-1 would grow if they were playing against better teams. On Wikipedia and in Truth&Rumor, the cities that are mentioned for MLS expansion are Milwaukee, Miami, and Cleveland. All of those cities have USL First or Second Division teams.
Say, for instance, Real Salt Lake finishes with the worst record as expected, and the Portland Timber win the USL-1 as expected, Portland would become the newest MLS team. If the Minnesota Thunder finish with the worst record in the USL-1 as they have now, the Richmond Kickers of the USL-2, who are in first, will move up to the USL-1. Think of up to 30 teams playing in the MLS over a fifteen year period instead of the fourteen currently in the MLS. This would spread the fanbase of the MLS from Montreal to Puerto Rico. This could raise the level of play if teams in the USL would get more money to spend on players. I think that making the league format more like the EPL could possibly bring the level of talent closer to the EPL.