I don't think people are arguing the MLS will become more popular than the EPL overall (world wide). It will become more popular than the EPL in this country though. Just having the teams here in your market and games at regular times will do that.
Seriously? You would rather watch baseball on TV over soccer? Football on tv is getting to the point where I only want to watch it if I recorded it and can fast forward through all the breaks. Basketball and hockey on TV are still fun to watch with plenty of action and similar time for the games as soccer. Soccer games are 2 hours max with 45 mins straight uninterrupted action, a short half and 45 mins uninterrupted action. Football, baseball and basketball recently have all been making efforts to "shorten" their games and provide a better viewing experience. Why are they doing that if their production is so great?
But as far as attending games, nothing beats a live soccer match.