What people fail to realize is that a vita+ps3 requires you to have a vita. the last time i checked, vita sales suck badly so the majority of people would have to buy a vita. Same thing with smart glass. the only difference is that smart glass will more than likely not be supported by most xbox devs. there is no reason to waste money by adding smart glass functionality to any 360 games when the 720 will be coming out next year(prob holiday 2013).
With the wiiu, all that extra money spent on handhelds/tablets will not be needed. its all built in the wiiu.