Earlier quoted context omitted.
4G and often 3G don't work in many rural areas. I expect 5G will follow the trend and be concentrated in high population areas, at least to begin with. I think 5G will mostly be in cities, with antennas on buildings. Masts aren't really practical for the network density required. I imagine as you exit a city you'll have the older infrastructure.
Rural areas are getting 4g. 3g is common, and 2g is even being turned off in some places. 5g will start coming to rural areas soon as some of the options make it more suited to rural areas than 4g. In 10 years we will probably be talking about 6g...
And history has shown that even if the 6G spec is unobtainable then in 10 years the carriers will water it down so they can claim "6G" capabilities [2,3]. I don't necessarily disagree with this because 10 years seems to be a good interval to introduce incremental improvements.
1. https://www.pcmag.com/article/360533/what-is-6g 2. https://www.howtogeek.com/399560/5g-e-isnt-real-5g.-heres-wh... 3. https://gizmodo.com/the-dirty-secret-of-todays-4g-its-not-4g...