Also, the higher frequencies are much more affected by absorption from little things like "walls" and "trees" which are occasionally part of the RF environment, so you're far less likely to interfere with your neighbors doing this, than you were with 2.4GHz.

Also the reason it makes such an enormous difference to put your AP in the same room, if at all possible. Sneak a cable somewhere, park the AP in the far corner of the room, sure. But with zero walls in between, it's huge.