Would the TV bands actually be useful for that? Wi-Fi has actually been going up the frequency bands looking for spectrum, from 2.4GHz to 5GHz and now 6GHz. Each one adds significantly more bandwidth (but worse propagation for a given transmitter power). If we were to make a "Wi-Fi 7R"[0] with 900MHz support, which is right next to some of the upper UHF TV stations in the US, wouldn't that be terribly slow and have lots of interference from overlapping base stations? I mean, 2.4GHz is already crowded to the point of unusability in a lot of dense areas.
[0] The R stands for "range"