I'm sure we'll hear from the same people who said the cloud wouldn't take off and that 4K was going nowhere.
When you say "cloud" do you mean the Internet in general, or specifically storing and backup of personal files on "cloud" servers? Such storage can chew up bandwidth very rapidly, especially if one has a data capped plan. Also, lots of people simply do not trust cloud services with potentially sensitive material.
But it's high tech! That's reason enough to use it! Singularity!
I'd lump VR/AR in the same category as 3D and video phones. The technology has been around for a long time, and it's an exciting novelty to play with. But when the novelty wears off, very few actually adopt the new technology for everyday use.
As for 4K, more is not always better. Digital signal processing and transmission did more to improve video than resolution. That is, even contemporary video that is below "Standard Definition" looks vastly better than pre-digital systems.
In my opinion 4K/UHDTV is overkill for the living room. I imagine it will become commonplace one day, by default, but right now the increase in resolution is not so striking that it will leave 2K/HDTV in the dust. I'm talking from experience—seen it, worked with it. (VR/AR, too.)