IMO what would normally make the bigger difference nowadays is probably not on the acquisition side but on the consumption side. People who watch stuff on cellphone screens mostly couldn't care less if you shoot that stuff using the iPhone 5 or the Arri Alexa. Meanwhile people like Ken would sure see the difference on his 70+" 4K TV and be able to nitpick everywhere. Yet there are consumer groups who would watch he exact same stuff on smaller screen TVs, desktop computer displays, notebook displays and tablets, all with countless combinations of different native display resolutions and graphic processor capabilities etc.
From all those groups, the groups of people who watch content on cellphone screens are collectively the biggest. And the dominant vertical resolution of the newest cellphones coming out over the past 2-3 years is only 1080p while the horizontal resolutions vary greatly depending on the ever wider aspects to accommodate user handling of the ever larger screens but none in the market currently exceeds 3840 pixels except for a couple or three phones from Sony.
My Asus ROG 2, for example shoots better looking 4K/60p downconverting to 1080/60p in better lighting conditions than the footage from my favorite loan camera, the Canon C100, shooting at 1080/60p. Would the final 1080p videos from both devices stand up to the full scale theatrical projection? I am pretty sure they will not but since all the materials I have produced for my clients or my own viewing have never gone into theaters so they have proved to be adequate so far. YouTube has for a very long time allowed content uploaders to view the statistics of the breakdown on the viewing platforms the audience use to view the videos, among a few other criteria, so it's been easy for me to see how the makeup of the audience of my videos is headed. Bigger screens or smaller screens. In my case it's been overwhelmingly going towards smaller. Not only the sheer size but also the resolution which has been ironically heading down to 1080p or 720p in this age of ever cheaper 4K or higher acquisition devices.