Exactly. 5G doesn't focus on increasing coverage but mostly latency. The mmWave stuff with the 1 Gbps+ speeds has a coverage of around a block, so that will only be used in super-dense areas.

From the competition section of the site, the sweet spot for WISPs seems to be just under suburban, where there's enough density but not quite cable coverage (or the local cable monopoly isn't giving their network enough TLC)