They could easily announce the game without any console attached... or simply mention things like "WiiU an other unreleased consoles" with no date or even remote time frame given.

True and I kind of expect it, though I also expect they will only show the Wii U version and then show the other two at another event even though all versions may exist. It just jumping the gun assuming it will be for the other new console with just the rumored project name.

Why exactly would they not make this for the Wii/PS3/360 which have a massive install base? Unless of course Disney hate money.

It would be silly to first hear publicly about upcoming hardware from a software developer instead of from Microsoft or Sony... I think it will be for WiiU

Ugh. Please don't post articles from the Examiner. It's pure trash, and anyone can write an article for them.
Disney announcing PS4 or Xbox 720? Ridiculous.

I suspect the author is making 5. I don't expect to hear anything official on the xbox or ps4 until around e3.

Well I think they are basing this off of the Infinate part of the title since that was one of the rumored code names/console names for the "720"

http://kotaku.com/5970308/report-disneys-infinity-project-will-combine-toy-story-the-incredibles-and-wreck+it-ralph-in-one-massive-cross+platform-gameworld

Here it is. This was originally project Toy Box.