I too have been watching the 900 MHz stuff as I have a number of unlicensed long range devices (1W ERP) that work in that range. The paranoid folks believe the FCC is trying to move all of the unlicensed stuff into the GHz+ range to limit long range communications. I don't subscribe to that opinion, I expect however that there is pressure from commercial interests on UHF and VHF frequencies.
I also believe you are correct in that the bulk of the use of the 6 GHz band will be UWB related and folks will exploit the multi-GSPS ADCs and DACs that are on Xilinx's RFSOC and Analog Devices is shipping. I read a pitch for a UWB "HD video extender" which was basically connecting a 4K display over UWB to a source rather than via a cable. That idea became a lot more viable with the current FCC order.
I also believe you are correct in that the bulk of the use of the 6 GHz band will be UWB related and folks will exploit the multi-GSPS ADCs and DACs that are on Xilinx's RFSOC and Analog Devices is shipping. I read a pitch for a UWB "HD video extender" which was basically connecting a 4K display over UWB to a source rather than via a cable. That idea became a lot more viable with the current FCC order.