Problem I see is the same argument for 6g. Suddenly 5g isn't enough. Suddenly all that infrastructure is going to be a waste.
Makes me think that people imagine setting up this stuff is magic and free. New fiber lines. Crews to trench and pull cable. Line crews to go on hundreds of thousands of poles. This isn't cheap both materials and labor.
Hell, my buddy and I got a quote about 2 years ago to run a fiber trunk line about 1.5 miles from the interstate to an office we had in Colorado. It roughed out to about 750k. That was with a friend who would do the boring. Easements, code, general feasibility due to existing infrastructure. Shit ain't easy or cheap. And we were in a rural area. I'd imagine an actual city is about two nightmares and a trip to a suicide booth.