It feels like wifi as currently constituted is the wrong solution for an urban environment, as it's too difficult to get the signal propagating just far enough without interfering with neighbours.
Seems like lower-power line of sight access points fitted discreetly to the ceilings of each room, powered and networked by cat6, along with smoke/fire sensors, would produce a more consistent, higher bandwidth, less interfere-y solution.
Does this tech exist already?
FWIW since moving to the middle of nowhere (1 house per acre) my wifi is awesome. I can get good signal 30m down the garden through two walls. So it's just not fit for purpose in high density situations.