There was a Rumour that it will come out for Xbox and Ps3 though
That could be tricky. I'm assuming ES:O is going to be subscription based?
Remember The Champions Online? Remember how it was developed for PC and Xbox, but never came out on Xbox?
The reason was that Microsoft do not allow developers to charge extra subscriptions for out of the box online functionality. You can charge for extra bells an whistles, but if your product relies on subscription fees to actually PLAY THE GAME then Microsoft will not allow it.
All basic online play, excluding specific DLC packs and maps, must be covered by the Xbox Live Gold subscription on all Xbox 360 games.