Ya, it's no surprise that fighting games have more spectators than actual players. Compare that to other competitive games that have both high player count and high spectators.
It really is just the nature of the genre, and how difficult it is to play them semi competent even as a casual. Id say the barrier to entry is quite high compared to other competitive games too. Some people feel compelled to buy a stick which is $100-$200 to even feel like they are on a even playing field. That cost + console price + game cost (higher if you import the latest ASW game). Ya, it costs quite a bit. While it's rewarding, it's hard to bring in people convincing them that they should spend X amount of dollars to start playing.
