It’s not like everything has moved off 2.4ghz - I’m in a SFH in a relatively low-density suburb and everything in my house that can be wired is, but I still typically see ~50% congestion on the 2.4ghz radios.
Yeah I just had a look and I'm seeing a reasonable amount of interference on 2.4ghz, very little on 5ghz, and then nothing at all on 6ghz.
My guess is people with large houses and only one wifi AP are probably using 2.4 when their devices are out of range for 5. But other people doing this probably doesn't impact you at all since you can just make sure you have good coverage for 5ghz and enjoy uncongested wifi.
My guess is people with large houses and only one wifi AP are probably using 2.4 when their devices are out of range for 5. But other people doing this probably doesn't impact you at all since you can just make sure you have good coverage for 5ghz and enjoy uncongested wifi.