* Water
* Sewer
* Power
* Internet
* Healthcare
* Fire
* Police
* Roads
* Education (added per /u/CodeMage)
Feel free to chime in if you can add anything I forgot.
Cheers.
I'll note that we should have explicit public subsidies for Internet and that I would much prefer to have public networks with private operators (to my mind that's heaven for competitive markets but politically impossible in the US).
For example, here in the UK, we have the formerly nationalised telephone network provider required to allow individual ISPs access to key parts of its infrastructure via local loop unbundling, so those ISPs compete for the contracts with individual customers. And while that infrastructure is indeed common and so in a sense a monopoly at that level, there are also multiple cable companies and mobile networks with completely independent infrastructure all the way down. There have even been a couple of impressive success stories where installing high speed broadband infrastructure was too expensive or risky in a certain geographic area for any of the big commercial providers to take it on but the local community devised their own solution, sometimes even finishing up with a better connection than what most of us get in big cities.
In other news, prices for Internet access in the UK seem to be dramatically cheaper than most places in the US.
These rents comprise something like 5-10% of city revenue. And so everybody gets what they want:
* The city gets a free 7% budget bump, and doesn't care who pays for it as long as it's too complex to be an election issue
* ISPs get a monopoly, and don't care that they play the scapegoat because consumers have no other choices anyway
* Citizens get better government services at lower tax rates. Sure, they pay for it via a backdoor tax on internet access but nobody really notices that and they direct their anger at the ISP rather than the elected government
Really the only way to throw a wrench in this system is something like Google Fiber. Nobody wants to be the elected official that turned Google away, because that is actually a sound-bytey enough issue that could come up at re-election. And Google, as a company that doesn't really care about being a profitable ISP, will only move in to a city if it gets a pretty good deal on the rents.
This is what I'm advocating for. A public last mile that any service provider can use.
Still a good list to have around so we can argue about where the line should be drawn. Kudos!
Education is tricky, and honestly, I don't know any better than the next guy how to solve the issue. What's important to one parent may not be important to another. Second language? Art? Music? Sports? Recess? Lectures? History? Religion? Critical thinking? What outcomes are important? Good test scores? Writing?
Healthcare is arguably a public good, at least as far as vaccinations and contagious diseases go, since herd immunity is a large way to fight them (especially for contagious diseases for which we have 80%-90% effective vaccines). Not so sure about other illnesses (like cancer) though. I'm personally for socialized medicine for other reasons (humanitarian), but I agree that the natural monopoly argument is not applicable there.
Orphanages
Mental institutions
Defense
My list would include: non-elective healthcare, food, housing (same as for food), electricity, water, local/regional transportation (e.g. for commuting to work), internet access and possibly basic internet-capable mobile phones.
Basically "natural monopolies" are certainly all candidates for complete socialization.
IMO non-catastrophic insurance should be abolished, the government should overcome the supply chain cycle ("Sorry, I have to charge $500 for this MRI because this machine cost me $4 million") by producing its own functional medical equipment and selling it at or under cost, and health providers need to get back to reality and charge face rates that real people can pay directly. And we all need to come to terms with the fact that some of the extravagance probably needs to be toned down.
However people are not willing to accept the consequences of hospitals that can't surge in catastrophes. When an EF-5 tornado hit my city 3 years ago, it took out one of our two hospital complexes. Things got ... rather intense at the other (http://stormdoctor.blogspot.com/2011/06/first-response-mode-...) but it being big, and stocked with otherwise excess inventory of all sorts of things, kept the death toll at ~160 instead of a likely 1,000 or so.