4k might never really be viable for mainstream. The regular joe user has maybe a 50" TV, and on those, you will never see a difference between 1080p and 4k.
You may see a difference on a 120" projector, assuming you sit close enough.
Cinemas today use 4k digital projectors (modern cinemas do, anyway). Their screen size supports the resolution. Cinema content is also designed with those screens in mind, so i dont worry about "bad" props looking bad on screen.
TV content might be another matter.
That said, if some company suddenly decides to push for 4k content on discs for home cinema, i won't be buying unless i managed to build a real mancave by then with a HUUUGE projector so that 4k is actually worth it. Don't get overrun by marketing.