Sounds reasonable to me.
MS right now is enjoying the success of the X360 and Kinect right now and they aren't going to lose that momentum right now with Halo 4 and other strong 3rd Party games coming out next year but despite that they know they need to release their next console close to the Wii U, which is around about max a year gap. They can't afford to leave a 2 year gap between it and Wii U since now the Wii U is more than capable of HD stuff and other things.
And obviously the same applies to Sony. The PS3 isn't going to slow down anytime soon with all the quality exclusives and 3rd party games coming out for this year and in 2012 and they've been saying all this PR stuff about, don't expect a PS4 soon, blah blah but that's all just PR talk. For the same reasons I gave for MS, Sony certainly cannot afford to leave a 2 year gap between the PS4 and WiiU release.
A 2013 release is a must for both consoles with 2012 reveals.
