In all honesty I think this could of been successful and they'd have shuttered it - Disney have been scaling back on console developement for the past few years and with Disney Infinity it's clear to me they want that to be their main focus now. As soon as Skylanders ripped up retail Epic Mickey 3 was never gonna happen - even if 2 hadn't bombed so hard.
The sales of 2 themselves are a combo of woeful reviews and the lower Wii software sales compared to 2 years ago.