Deploying software support for dynamic transmit power control would help a ton without requiring more wired infrastructure or more spectrum, both of which tend to be extremely expensive. When your laptop is in the same room as the access point, there's no need to be transmitting loud enough to clobber your neighbor's traffic. See https://github.com/thuehn/Minstrel-Blues
Not the only solution technically, put up grounded metal wall panels or wire mesh on the walls. Mounting tape/nail them on the walls if you live in an apartment.
Well it might. Google centrally manages each OnHub to actively pick the best channel, where "best" takes into account nearby networks and their channels and other spectral problems.
