Cant see anything happening - they can't even get their act together on keeping the ATV current with worth while content. its basically good for mirroring and using their store only.
Not a chance just like the OUYA wasn't a console killer. Gamers buy consoles so they can play the best games at the best quality and those won't be on a $100'ish set-top box.
Never going to be console killer, but it would put a dent in them for sure. I think Nintendo has the most to lose, if not for the exclusive characters Nintendo would already be dead.
It could be a lot of things if it would just get released