One way to encourage just that sort of city planning is, in fact, to price externalities appropriately. It's not actually cheaper to build and live in sprawl, it's fantastically expensive. But we don't charge those costs based on usage.
I can spend 400k to buy a nice four bedroom house with a garage and a basement on half an acre sixty miles from work, or 400k to buy a beat down 1 bedroom condo ten miles from work (nothing near the area where I work is under 900k)...
That's not really a city planning issue, it's just the way things are in hyper-urban areas.
I hope so much that I can pull off a remote job in the next year or so -- believe me, I'd rather never drive if I could.