The thing is that it was a bit on the expensive side & it needed the i-device to upload effects into it. They had a long list of issues with the ipB10 unit regarding apple software & connector issues. I think the connector issue also carried over to the iStomp. I'd bet having the ability to have to be stuck with an ipad/iphone/ipod interface is what caused people to stay away from it the most. Besides that there was competition like L6 M9, Zoom G3/MS50G in that price range which offered more features for same or less price.
Digitech is moving away from the i-thing, so probably wanna empty their stock, hence the drop in price, plus the free giveaway of those 20/30+ downloadable effects.
It was a nice concept but apple keeps redesigning/updating/improving their devices. Tieing a non harware evolving unit(istomp/ipb10) with a random evolving unit(ipad/iphone) is just not a very thought after plan IMO