It’s uneconomical in an already built out area or a non central planned economy, and also the US is special case since we have dirt cheap natural gas that is used for heating.

Digging up streets to run distribution lines, running service drops to every existing house, installing a heat exchanger and valves in every house is astronomically expensive given the amount of energy used by a single residence.

If you’re building out a new neighborhood on a greenspace plot, installing the district heating/cooling piping is much cheaper since you’re already laying electric, water, sewer, and mane gas lines.