Atari has some things going for it right now that the Ouya didn't. Atari has history behind it, the Ouya didn't. Atari has a backlog of hundreds of games to ship with the Atari VCS whereas the Ouya had nothing really, at least not recognizable games. And the Atari VCS is a lot more powerful than the Ouya and can do a lot more. And also there is something about the look of a console that draws people. The Ouya was a stupid pathetic looking box thing that didn't appeal to people. It looks like Atari tried to mimic the Xbox controller for their modern controller which might be a good thing for them given the fact that Xbox controllers have gotten generally good reviews.
Obviously there is a market for nostalgia and Atari has taken note of the success of the NES classic and SNES classic. And now Intellivision is coming back with a new console as well. So I think that's great, the more the merrier.