Controller support. Hmmmmm. I'm willing to bet we're going to see some combination of apps (games) that support Airplay and these controllers along with Apple TV APIs in the fall.
And that's when XBox and Playstation will have their lunch eaten before they even realized they were served a plate.
The upcoming XBox and Playstation? Unlikely. While mobile hardware is getting more powerful steadily it still is not going to stand up against coming generation consoles (which are functionally mid low-mid gaming PCs). There are a few things that will stop iOS with a controller from blowing away these machines.
• AirPlay video lag/delay. While good AirPlay is still laggy enough to not be viable for "serious" games.
• Storage. BluRay based games can support anywhere from 20 to 60 GB of data. Apple hasn't even released a 128 GB iOS device. Most folks aren't going to sit around and wait for a 20 GB game to download. This means that texture qualities will never be on the same level as a dedicated box. Even taking PC games as the size we're still talking 8+ GB on the low end.
Forget taking the market away from the two top players. What this really could do is put the hurt on Nintendo. Whenever the A7X processors drop they'll likely be able to perform on par with the WiiU. It would also remove the last obstacle to iOS devises going head to head with Nintendo Handhelds, lack of buttons. Even still there is the storage issue as above, WiiU disk can hold 25 GB of content/textures.
I see this a far more troubling to Nintendo then to Sony or Microsoft. The 16 GB $229 iPod Touch is not far off price wise form the NEW bigger screened 3DS. Depending on what a controller case will cost it will be a hard battle. You can almost kiss the PSVita goodbye.