As much as the tech demo is very impressive, I suspect that the game will be able to run on some very modest hardware ...
The core techical feature of next generation game engines (in my opinion) is probably advanced level of detail systems that are (probably) heavily dependent on tessellation. There are two reasons for this, this makes it far easier to scale games to run on hardware with wide ranges of capabilities (produce a game that can run on the current HD consoles while showing off the capabilities of bleeding edge PCs), and (since you're not wasting processing power displaying details people can't see) it allows you to use the processing power to display more detail that people will notice.
To use the HD consoles as a benchmark, if you split the scene into (roughly) 3 equal parts based on the processing power used and evaluated the near, middle and far 1/3 of details you would (probably) find that the near 1/3 could see substantial improvements from increased detail, the middle 1/3 only saw modest improvements from increased detail, and the far 1/3 saw no improvement from increased detail. Now, hypothetically speaking, if you have an advanced LOD system in place you can direct most of the improvements in processing power to that near 1/3 and (effectively) get a much larger impact than you would have previously been able to get from a similar performance jump.
While I have no doubt that the tech demo is running on very high end hardware, and results like that are probably out of reach to the Wii U, PS3 and XBox 360, I wouldn't be too surprised if any game based on them could be released on all three platforms; and the Wii U version could see some of the advantages of tessellation on increased noticeable detail.
