I question some of the locations of the soccer stadiums - the few I know of are so far away from their host city.
The MLS site has attendance numbers for the the games - NY has some up in the 50,000's which is pretty good, but much higher than other cities. UF Football packs 80,000 on game day at the Swamp, as does FSU, UTX, UTenn, etc.
Chicago just opened a 20,000 seat stadium for the Fire. So what if Soldier Field (Bears) is nearly four times the size? Should I forego attending minor-league baseball games because they're too "little?" I have more fun at them than at MLB games . . . and I don't have to spend $150 just to have a good time.
The Dallas Burn and Columbus Crew have nice soccer-only stadiums. I remember the days of the old Fort Lauderdale Strikers in the NASL, playing in Lockhart Stadium, which was mainly used for high school football games.