Yeah, I agree with you. But it is so far behind most other sports I am not sure if it is appealing enough to Americans at the moment to follow it religiously, or pay any attention to it.
I have been a soccer fan since the early 2000s (as early as I can remember) and I watch EPL, Serie A, and La Liga regularly, (every EPL game each week), and I have never been interested in the MLS because of the weird league structure and inconvenient game times. In fact, Lampard initially attracted me to NYCFC. Now like you said, it is largely because of the size of the United States and all that; but to me, and many other soccer fans, there isn't anything better than waking up early Saturday and Sunday and watching our favorite teams play. I'm sure that's the reason that many mid-week EPL games are the lowest viewed and they always play the biggest games during the early weekends (so the most people can watch).
IMO, the way forward for the MLS is to attract people that already love the sport (other countries), grow it into a major league, and then the United States' sports fans will take notice.