For the second part of the answer, I believe the general problem is the nature of a 'loop' -- the further it goes, the more likihood of shifting, or some sort of a problem, and when it happens, it'll take out multiple homes, and require extensive work to figure out where the problem / leak / whatever is.
The other issue is a simple question of what the responsibilities of municipalities are. Now, I can say this as I'm a town commissioner, and so an elected municipal official -- I think this is completely outside the scope of our municipal charter. The closest thing I can think of is that there was a development where they wanted to put in a dry pond for water storage to deal with possible flooding issues, and our town (before I was elected in) agreed to foot part of the cost of their connection to the storm sewer system (which is run by a larger entity, on the scale of the county, not the town). The reason was, we didn't want the nuisance of an improperly maintained dry pond.
In that case, the local water company woud be dealing with the long-term maintanance, not the municipality ... and I have no idea what would be all of the issues of maintaining a ground loop long term. but I know it's not something I'd be willing to get our town involved with anytime soon. (personally, yes, I'd be willing to do it to my own house, even with the comment about a house blowing up; but I don't think it's in the best interest for the town to get involved with ... if a new development wanted to do something, and have it managed by a homeowner's association, that's fine)
update : Fine, fine ... you don't care about the political reasons ... so here's my thoughts from an engineering persepective :
Electricity, sewage and water benefit from a central processing location, rather than smaller individually sized solution, assuming there's sufficient density of the places being transmitted to (using recent technology; it's possible it might change in the future for electrical production). In some cases (septic), it limits building density if you have to provide for it on-site, so there's benefit it moving it off-site entirely. In the case of geothermal heat pumps, you actually need the ground contact for the heat exchange, and unless you're transporting the water at sufficient depth, you'll have signficant transmission losses.
If a town/county/state whatever were to get involved, they'd be better off not trying to build a large ground loop and trying to maintain it, but instead either contracting for drilling for their residents and businesses, or including such expertise and equipment necessary in their budget, and doing it in-house. (but then we get into issues with should the government being doing it, or competitively bidding, but this one isn't supposed to be the political answer)