Getting merchants to sign up should be really easy. But, how do you get them to pull the plug on Visa/MC? They'd have to be sure that they wouldn't lose too much revenue, and that would require a significant portion of the card-holding population to have a revolution card. And, you'd have to deal with corporations that only have one of Visa/MC/AmEx for corp purchases.

I suppose merchants could feature Revolution prominently to increase its use, but they can't make it too hard to use other cards or they'll lose out. And, given my 1%-2% bribe for using my Visa/MC, why wouldn't I look for the little button down in the corner?

Discover (Sears) was able to introduce a new card, but they too the opposite route -- they bribed consumers to use it. So, even though it has basically the same fees as the others (IIRC), consumers could see an effectively lower price through its use.