> How does "unincorporated" work here? Is there not a local authority? Is this the cost of being outside a property tax area?

I don't know the specifics of Arizona, but this is common in California, and likely they are analogous:

California is fundamentally organized into "counties". Some (Irvine) are old Spanish land grants. One (San Francisco) is a city. They can (rarely) have exclaves, like San Francisco's exclaves in the sierras and the SFO airport, entirely surrounded by San Mateo. Basically the State deals with counties.

"Incorporation" is just forming an organized government exclusively coextensional with a piece of land (you can also have a government "corporation" with somewhat arbitrary boundaries, like a school, water, or fire district; I don't know of any of these that cross a county border, though it's not like I pay much attention to them). It has some sort of election system for the people in that government.

The majority of the counties are themselves not even incorporated and are run by a default set of rules set up in the state constitution and some laws passed by the state assembly. They have county sheriff's offices; some have fire districts, and that's often about it. I used to have a house in Calaveras County which is not incorporated, has a single city (i.e. incorporated town), though the county seat (capital) was not incorporated and is just a labeled place. Neighboring Alpine County's seat is east of the sierras and inaccessible from the west half of the county due to snow for about half the year.

The densely settled counties are of course incorporated, but since incorporating a town is up to the folks who live there, a lot of places inside the counties tend not to be. They get county services (big, incorporated counties have social services, sheriff, etc), state services, and are often covered by a local school district or fire district. They pay the same property taxes as anyone else; towns don't get to set or collect those anyway. They may have a water district, or may not. For example, Menlo Park has at least one neighborhood with its own (well water) water district as the neighborhood was built by subdividing someone's ranch, as Stanford was.

A few notable consequences in the Bay Area:

Redwood City surrounds a small unincorporated bubble of a few city blocks. My theory is that RWC has a bunch of environmental rules and needs a place that doesn't follow them. That unincorporated area has a couple of automobile paint shops, a mobile home park, some machine shops, print shops etc. It of course doesn't pay any city taxes (if there are any; I worked in that bubble for a while and so we didn't even consider of RWC had a business license or tax -- we just ignored them).

If you've been to Silicon Valley you've probably seen that next to Palo Alto is East Palo Alto with a very different demographic. Into the 1980s it was just an unincorporated region generally referred to as "unincorporated Menlo Park" (there are still unincorporated regions next to MP referred to that way). Just because it had that name didn't mean it had any connection to Menlo Park, though I think they did get some services from MP. It was mostly light industry like helicopters and machine shops. Some folks living there decided they'd be taken more seriously if they either joined MP or incorporated. They were going to call the new city Nairobi, but some wag got the clever idea to call it "East Palo Alto". They couldn't possibly join Palo Alto because they are in a different county (Palo Alto's border is also the county border) but the name choice was inspired.