Having lived here for 11 months and been to a handful of New England Revolution games, I can only say the quality on the pitch is poor, leading to crowds of around 10 - 12,000 (doesn't help that the stadium is in the middle of nowhere with no public transport to get there!)
You only have to look at the 1970's US Soccer league with Pele, Bobby Moore, Tueart etc etc etc.
In short it was a circus that people came to see, but once the main acts left, so did the audience. I actually enjoy the atmosphere at the Revs games (despite the crap songs sung!) in terms of there is a genuine hardcore trying to keep it going.
It's a balancing act of not solely having a product based on certain players from abroad performing like seals that will bring crowds in and nurturing and developing a league that doesn't have the glamour therefore the smaller crowds too.
The media doesn't help. Here in Boston, you have the big 4 teams - Patriots, Red Sox, Bruins and Celtics.
The hostility to the Revs in the local media is very evident in their complete blanking of the team. Yet the football, baseball, ice hockey and basketball get wall to wall coverage on local stations / news.
Evidence of this was local news stations were reporting on the Liverpool v Roma game last month at the Red Sox stadium 3 days before and every day leading up to the game - it was big news. The Revs score from one of those evenings wasn't even given out and it never is.
Anyone thinking the MEN has an agenda against City should be a Revs fan and feel the agenda against ''soccer'' from newspapers / TV and radio stations!