On a recent residential Wifi installation in a Mission District apartment not only was the 2.4gHz spectrum saturated, but the 5gHz range was as well. All of the neighbors had their access points configured to use 80mHz channels at max transmission power. Attempting to provide coverage in dense metro environments in the 5gHz spectrum with a single high powered access point is a bad idea. The correct deployment technique in this spectrum is multiple lower power access points tuned to provide coverage to target areas with the same SSID with narrower channel widths to make room for neighboring networks.
Fixing Wifi in dense urban environments