Two player sticks suck because you're always fighting for space and being cramped. Also (regarding 2-player X-Arcade) some people stink, and I wouldn't wanna be too close to them, you never know maybe it's their strategy. You never got to worry about that with 1-player units because you can distance them far from eachother, also, you or your opponent can always plug in a game pad.
If a company can save 20 cents they might do it, but if they can save 30 dollars they will do it. Whatever type of components are used in those sticks look so much like the STP, Lorenzo, Wico, Happ, and Atari stuff that I feel that the uninformed customer may mistake the two. The arcade stick business doesn't look too lucrative at this point, even X-Arcade's products accounted for less than 1/1000 of 1 percent of sales at a local business I know of.
I believe that there is great potential for high end beautiful manufactured arcade sticks, and consoles. If there are people actually buying $10,000 internet refrigerators-a $2,000 fine-furniture grade, full sized mame would probably find some buyers.