> And if there's a > market, why is it that those customers just happen to not need six button > controllers?
The jamma connector just has 4 spots for each player's buttons. When a game uses more than that it has to have a custom extra harness/wires. Superguns are generally for standard jamma games, not every arcade game ever. Even within just jamma you'll run into other problems too with refresh rates on lots of games. The games were made for an arcade cabinet. Superguns are hacks upon hacks.