Does any of it have to do with the spectrum becoming available? After 2.4GHz and 5GHz, I have no idea what else the latest/future gens of WiFi are using. As some tech like 2G is no longer in operation, that spectrum was opened up. There are other frequencies that have become available where operating the older equipment that used to operate there is a big no-no now. There was a frequency range used by old wireless microphone systems that are banned at locations.
Just taking a swing at it, but I don't play that sport so probably a big whiff
In regulatory regions where it is usable, Wifi 6 (802.11ax) added some 6GHz channels. Wifi 6e extended that to roughly the entire 6GHz band, for ~1GHz of contiguous RF bandwidth in that area alone.
The "old" cellular bands aren't generally open, at least in the States. We tend to use them for newer licensed stuff in cellular-land instead of the old licensed stuff we used to do. (Old modulation techniques die out and get replaced, but licensed RF bandwidth is still licensed RF bandwidth.)
> In regulatory regions where it is usable, Wifi 6 (802.11ax) added some 6GHz channels.
'Plain' Wifi 6 (non-E) had zero 6 GHz. If you think otherwise can you produce a citation?
Edit:
* https://en.wikipedia.org/wiki/List_of_WLAN_channels
You're right. 6GHz wasn't usable as a part of standardized wifi until 6e.
I'd like to choose option C: I thought otherwise, and I was wrong in thinking that. I'd like to submit my previous comment, just above, as a citation demonstrating the incorrect thought process. ;)