Over in technology, we're rapidly marching towards cheap household-scale solar panels and batteries, commodity autonomous driving technology, and cheap electric cars. Elon Musk's satellite constellation will deliver decent internet service regardless of the population density/economics needed to support fibre buildout. Telepresence is already good and keeps getting better.
The society coming down the line is one made of energy-independent prefab houses with no particular constraints on location (so they'll go to where land is cheapest), drastically improved freeway throughput (autonomous cars can pack much more densely), and car interiors not much different from small apartments (you'll be able to eat, sleep, and work while the computer drives).
So, as it gets easier to live farther from work, the economic incentives for everyone to cluster into a few square miles will diminish greatly.