Diminishing marginal utility is certainly a thing, and I would counter argue that the longer it takes for a technology to be transformative the less likely it i

Diminishing marginal utility is certainly a thing, and I would counter argue that the longer it takes for a technology to be transformative the less likely it is actually needed by society. At a certain point in time the answers to both of your questions are going to be "no one". Do you need a 32k resolution screen? Do you need a 8.4GHz processor? Maybe, maybe not. If you keep bumping the numbers up you will eventually see an imperceptible difference in performance that won't justify the costs to build it from the oems. The only real use case I've seen for 5G has been people live streaming themselves from a cell phone in major cities. That didn't seem possible before, but so far it's a small niche not something transformative. The only other use case I could think of was streaming live sports from people's cameras and making a digital television network out of that. However, I think you would likely get kicked out of every stadium in the US if it caught on as you would be undercutting the major source of revenue for most sports leagues.