Nintendo can't because their hardware as good as it is now will not be tolerated by devs or consumers in 2016.
MS needs to make a new console because of the RRoD stigma.
Sony could make their system as a gaming standard which lasts for 10 years (not 6 then new console) which is something that could attract people who hate to change consoles, then make PS4 a fairly expensive machine too and make the same 10 year promise (advertise it as the buy it forever machine).
Plus it's still gonna be blu-ray player even when they quit making games for it (and a cheap one at that in 5 years), heck people will still be using PS2s they get from yard sales for DVD players for years to come.
The problem with any of them skipping a gen is whether the 3rd parties will still support their system in 2016.
Kickin' Those Games Old School. - 201 Beaten Games And Counting
