>The solution is of course to get a communal system.

If it's that simple why is Austria not doing this in the cities? I don't know any voter who opposes cleaner air and cheaper heating.

It doesn't work this way. Dense cities just don't have enough space for geothermal heating. It really works for single-family homes only, or maybe just a slightly more dense areas.

Not to mention that city infrastructure is WAY too expensive to build, anywhere. You'll spend more money on planning than on doing the actual construction.