Here is a recent news item about the 5G thing:
https://www.usnews.com/news/business/articles/2019-04-12/fcc-to-hold-big-5g-auction-spend-20b-for-rural-internet

As yu can see from the link, it suggests this will help rural internet coverage.

But I am very doubt full.
Why don't the 3G and 4G provide coverage for all of the USA?
Is there something I am missing here? 

Isn't there an economic reason, to do with AMOUNT of revenue generated, versus COST of provision? It MAKES business sense to plant cell phone network masts ("towers" in USA) in areas of high population, and (often forgotten) provide network infrastructure to service them, (fibre links, routers, etc), and crucially, power. Less so in remote rural areas. You don't build a railroad or freeway to every little village or hamlet. If it would take 100 years to get, in usage charges and revenue from selling plans, to pay back the cost, ain't gonna happen.I agree. It will not happen soon enough.
Here is a blurb from PC Mag:
Quote

AT&T is kicking off the 5G revolution with its launch of America's first 5G mobile hotspot on Dec. 21. Initially, this new network will only come to dense parts of 12 CITIES, and the millimeter-wave spectrum that AT&T is using is more SUITABLE for cities and suburbs than for the countryside.

But with great speed comes great complexity. Because the millimeter wave used by 5G transfers information at short distances, more transmitters and base stations, signal repeaters, are required. This could result in prolonged deployment times and spotty coverage, or no coverage in rural areas. 5G waves are also more susceptible to atmospheric interference and weather conditions like rain.