The difference between 1080p and 720p is not so noticeable on an HDTV, very noticeable on a PC Monitor. Im using Wind Waker HD and Sonic Lost worlds for reference. Perhaps it also depends on the type of game.
As for MK8, a lot of WiiU fans are just starting to accept that minus extra RAM, eRAM and a few OpenGL 11 extensions the WiiU is barely a step up from the 360 in terms of pure rendering power. Fans thought NSMBU would be 1080p, nope. SMW3DL 1080p, nope. Pikmin 3, nada. Wonderful 1010? No. MK8 1080p? Probably not. Bayonetta 2? highly doubt it. Numerous 3d party games, hell no. The Wii U will have very few native 1080p 3D games. Bar Wind Waker I think there's none. Like I said Wii U fans and customers are finally accepting this so it wont be a problem from the Ninty crowd anymore.
On the X1 side its simply because of the premium price compared to the PS4. Seems like a rip off considering. That said games like Killer Instinct use artstyle, 60fps and crazy DX11 effects to side step this. Even Ryse looks great despite being 900p. MS fans wont be too bothered by this soon either
PS4 fans? Its nice to have something to brag about. I suspect they'll rub this in everyone's face every chance they get. Though KZ SF at 900p and constant 60fps would have been better imo.
I predict that the Wii U will sell a total of 18 million units in its lifetime.
The NX will be a 900p machine