We can if we tear up most of the cities and small towns that exist today, like I said.

The cost-benefit of doing so.... takes a long time to pay off (if ever) and forcefully dislocating people like that generally isn't popular. Public transit would be great, but the argument needs to be a lot more realistic to how we retrofit public transit for our existing cities, and focusing future growth on making it compatible with public transit. It's not realistic to say "We just need more public transit, Europe has it figured out" when our cities and towns are laid out way differently. Obviously re-zoning certain areas and moving businesses closer to suburbs is a start, but it isn't going to be as simple as "build cities like Europe" because the cities are already built.