Re: No point having this in phones
You don't need the ultra high frequency bands to max out at insane speeds. Using more reasonable bands like 3.5 GHz should be ideal, as the antenna can be sited where it has the best reception on the outside of the house, won't move, and isn't restricted to the form factor of a cell phone.
In rural areas you don't have "a street full of 4K TVs", and even assuming 4K takes off the way HD did (which is by no way assured) it isn't that much bandwidth. Netflix is using 15.6 Mbps for 4K, EU satellite companies seem to be using 18 Mbps, Directv in the US is the outlier using 30 Mbps. Even if you had a family of five all streaming a different 4K program on Netflix a 100 Mbps connection would be sufficient.
In built up areas you wouldn't have much need for this, since it would have to be fed by fiber anyway. If you've got that fiber, you can use DOCSIS 3 or G.fast over existing copper from a small cabinet every few blocks. But if you have utility poles, nothing stops you a providing from sticking a tiny lower power 5G antenna on one every block or two, and siting antennas on the houses so they have line of sight.
Biting the hand that feeds IT
