The main reason I put UHD adoption at 15 years away, is that we another new technology on the horizon: OLED
Both OLED and UHD obscenely expensive at the moment, so practically no one is actually going to buy one. OLED is (practically) the same as the AMOLED screens you get with your smart phones, but it's a lot more expensive to create over 40 inches instead of 5. Without bothering to go into why, with OLED TVs the blacks are blacker (or quite simply black) so the contrast ratio is meaninglessly perfect, and they can be extremely thin as they are not backlit. With OLED TVs, all that lovely 1080p content is rendered beautifully.
You can also have curved OLED screens which in my opinion are (probably) completely pointless.
UHD TVs need new content, otherwise they are expensive current generation TVs and that new content hasn't been created yet. They are as expensive as OLED, although further along the development tree and so could be closer to mass-market manufacturing. They are also mostly being made ridiculously large; 50 inches plus, purely so the UHD content actually looks (noticeably) better.
Again, with OLED you could have a regular 32 inch or 42 inch TV and the picture would seem fantastic, even with current generation content.
Of course you could have an OLED 4k TV, which probably would cost a fortune, but it's practically what I would recommend. If you want a 4k TV, why would you not buy an OLED one? There is little 4k content at the moment, so you are buying a several thousand pound machine which will be outdated as soon as the content arrives, because OLED 4K screens will be the norm.
5 years time OLED, 15 years time OLED 4K? My guess anyway.