That and the fact that it's boring as hell to watch on tv, and I played soccer for 15 years..
Watching soccer, NASCAR, bowling, and cycling are even more boring than tennis, golf, baseball or poker..
i actually really enjoy watching soccer on TV. granted i don't watch a lot of MLS, but the upper level euro leagues, world cup, euro cup, etc. are great TV imo. outside of football, i'd put it against any TV sport. the only reason i pay much attention to basketball is because of MSU. i couldn't care less about the NBA. i might check out some playoff games in 7 months.