only feasible reason is online structure.
X360 online structure is better than wii U's and PS3's, and this game is always online.

With the PS3, it most likely came down to time. A PS3 port would take quite a bit longer so it was probably cut so they could make their deadlines. I don't really have a problem with that, as it wasn't announced for the PS3 from the beginning.

With the Wii U, it's probably a combination of factors, including a lack of faith in the sales potential of the platform.

Wasn't it Ubisoft that stated an X360 to Wii U port cost just under $1.3 million?

At $20 per unit publisher share (of a $60 game), that's just 65,000 units to make profit.

Well if awkward architecture is the reason then that's fair. Wouldn't sell much anyways.

Wii U owners have not bought the games, so this is the result of an ongoing problem.

And PS3 owners?

Honestly, at this point, I'd respect the developers more if they just said, "Because we don't want to."

First of all I hope you know that the real reason for no wii u version is because 3rd party does not sell well on Nintendo systems. Now they said, they chose the 360 because it is closest to current gen systems in terms of architechture, unlike the ps3. They just included wii u with the ps3 in that statement to cover up the real reason. 

This isn't about lazyness or not knowing how to develop for a console.

The lack of a Wii U port is pretty obvious. The game would be lucky to sell 100k copies on the wii u. And most of its sales would be at bargin bin prices. Porting it over wouldn't be worth the cost.

The lack of a ps3 port is probably because they didn't have time to finish making the port on the ps3 without delaying the game and unlike the 360 they won't run into any issues if they make a late port for the ps3. If the 360 version of the game ends up selling well, I fully expect a ps3 version to eventually come out. If the 360 version flops, they will probably skip the ps3 version.

It's okay. With games like DriveClub and Project C.A.R.S, Playstation will have plenty of racers to go around. At least it's still coming to the PS4. Now had Ubisoft made some excuse as to why THAT version wasn't coming, then we can chalk it up to MS. LOL