Requiring a 100 meg upload really changes up the dynamics of the WISP capabilities, resulting in fiber-only at a cost increase of 20x - 40x... for something that isn't needed.
I will admit to zero WISP experience but wifi is symmetrical speed up/down so why wouldn't a WISP not also be?
Wifi 6E higher speed and base control of clients, subchannels, simultaneously transmission from multiple clients etc. All good stuff that should allow a WISP to deliver much higher upload.
As soon a certain threshold is reached, higher speed will not cause more utilisation of the airwaves.
The WISP will need to invest in wifi 6E gear, which I suspect is the real problem.
Regards
Baldur