Also to remember is that most of the teams in the USL are reserve teams of MLS teams, so the team will always be changing as playes are called up or released and new players coming in, there would be no loyalty to the team.
Interesting to note 3 of the top 4 in attendances are Independant franchises.
If the Fury was an independant franchise would they draw bigger crowds than if they were a reserve team of say the Montreal impact?
Ottawa will be an independent club in USL. So the team won't be having people "called up". Fury are the Fury and noone's reserve side.
CSA which btw isn't currently allowing canadian teams to enter US div 3 (which USL currently is, could be 2 next year), but might to help tide Ottawa over until the CPL. Also has a rule, that no canadian club can have a farm club/reserve team in another city in Canada. Even without that rule, it isn't happening anyway.
BTW there is a big difference between the Affiliates and Partnership clubs with USL/MLS.
The teams like TFC II, Swope Park Rangers, Orlando B, FC Montreal are pure reserve sides/B teams for the MLS club.
While Affiliates like Sacramento (who will be Independent next year), St. Louis, etc signed agreements with an MLS club to allow them to develop players for them in exchange for something (coaching stuff, developement, etc). An Example of this would be Sacramento republic having 4 SJ Earthquake players loaned to them for the year, the rest of the team are just straight up Sacramento players.
So Affiliate clubs run the gamut from being pretty much an independent club (having a few loaned players) to some level of integration (much more loaned players, some coaches)