This is not the case for 4g since the much lower frequencies (with much lower data rates) go much further meaning that the given last mile monopoly in an area has less of an effect on the 4g service.

If a cell phone carrier builds all of its own infrastructure to supply bandwidth to 5g towers, they are subject to all the same difficulties and delays as existing ISPs. This means that build out of 5g as fast as home internet will take decades and many areas will have only one or two options (same as the situation is with home internet).

The waters are muddied by the fact that carriers use “5g” to refer to what will be a wide range of service levels, but right now are only hyping the fastest possible imagined deployments.