There is significantly more spectrum available for wifi in the 6ghz band than in the 5ghz band, so even if we moved everything off of 5ghz and ignored the attenuation benefits of 6ghz, we'd still have significantly less congestion on 6ghz than 5ghz wifi. In my apartment, my laptop can see ~50 wifi networks, we need some spectrum elbow-room to spread that out.
https://en.wikipedia.org/wiki/List_of_WLAN_channels