Waiting for 16K, 4K is clearly just a passing fad.
Ha,,,, don't forget 8K which has been at the last two CES shows and well 4K has been out since 2011/2012 (first year I went), now granted I think there was only one or two vendors at the time. But that number has increased to the point everyone had a 4K tv. Same thing with 3D tv's. They were very popular over the last few years.
4K is not important to me. I do not have anything that can display it, blu-ray, tv, receiver only supports 1.4a hdmi, 4k rips, or any other media. I do have netflix but they only have a few shows that were shot in 4K. Marco Polo I think was the first or pretty close to being one of the firsts.
I will wait and see if 4K really makes an impact and can penetrate the market along with adding the necessary content. Only time will tell, but for me, the time to upgrade all of my equipment is not now.