As of today there are over 8 million references to 6G, the next wireless system, the one following 5G. A clear indication that although 5G has not really started the deployment research is not stopping. Today there are several trials on 5G, Verizon has announced the start up of the 5G service in a few areas in Chicago and Minneapolis in April but it will be more of a trial than real service since 5G phones are not yet available, the Samsung Galaxy S10 will become available somewhere before June, and the first users will have to connect their 4G phone to a little box receiving the 5G signal.
Obviously it will take at least 15 years to have the rolling out of the first 6G systems (that means around 2035) and 5G will keep growing for a few more years after that (ETSI estimated a few years ago the peak in adoption for 5G around 2040), as it is now happening with 4G that is expected to grow for a few more years, at least till 2025.
Personally, I do not consider 5G as the ultimate solution, just as the best we will have for the next decade. Actually, I consider 5G as a transition system, the transition from networks built by Telecom Operators in a top down way to the future networks that will be built bottom up, with the core network consisting of software, owned by a few large (non telco) companies, possibly running/hosted on the big data centres of the big 9 (G-MAFIA and BAT) to which I hope a few more (1 or 2 from Europe) will be added.
In the future, terminals (no longer terminals but network nodes and creators of networks) will be even more important making up the communications fabric that my grandchildren will be using every day. Big connection pipes will still exist (for as long as I can imagine) but will be owned as a public resource, a commodity that has to be provided by any Country, the same way highways and roads have to be provided and maintained.
I made this point a few years ago, saying that 5G is just the system before 6G, not the end of the line in G numbering, and it seems I was right, but fully open to your comments and possible disagreement.