1) No one owns a 4K TV, especially in the console demographic.What makes you so certain? Next-gen consoles are based on AMD hardware, and AMD cards that you can get for under $100 (7750) support 4k resolution.
2) The lower end 4K resolution is more than double the pixels of a 1080p TV, and would require an incredibly powerful setup to run at 30fps which is what a lot of console games target. There is no way that the consoles will be able to deliver this level of power and still be affordable and fit into the power/heat requirements needed. It's just not feasible.
They might be able to do 4K upscaling or something but the games won't render at that.