Q? Are the territories covered by ISPs already governed/and/or assigned by the FCC or other regulatory agency?
Where I used to live, the only viable options were AT&T and Charter, where I am now, its Time Warner and AT&T.
In fact, my current house did not formerly have Time Warner, and they had to send a tech out to my address to see if I could get their service. AFIAK, every house east of me on my street has time warner and every house west of the next house west of me has Charter. It seems that These companies have carefully defined boundaries where they can operate which pretty much makes them defacto monopolies.
If in fact, (I'm not entirely sure) these territorial monopolies are a result of government regulation, is more government regulation the correct answer?
Territories covered by ISP is controlled at the state and local level. Local governments demand things from the ISP (wife getting a no-work job, free service for the government buildings, etc), ISP provides the requests, ISP gets a monopoly. Biggest two issue is access to the utility poles and public right of ways. It is not possible to build a landline ISP without access to the poles and public right of ways. Control of the poles is what enforces the monopoly. They will always be willing to grant you access, at exorbitant rates after a brutal administrative process. Typical example would be that the poles would have to be surveyed. If a pole needs replacing, you'd need to pay for the entire replacement (not a portion of it, ISP and local govt pays nothing). Then your monthly rate is typically 5x-100x the actual cost of maintaining the pole, including all overhead. If there's something the ISP or local government wants but doesn't want to pay for, you pay for that too. New retaining wall nearby, drainage, erosion control, etc.
Wireless is assigned by FCC, and states have extremely little jurisdiction. There is also state level utility agency control. In general, they're in the pocket of the utilities, but sometimes you get results from them.
Telecommunication companies are given a mandate to provide telephone service to nearly every house. It's handled mainly via Universal Service Fund (USF). This only applies to telecommunications (ie POTS phone), it does not apply to internet service. Originally, “universality” of service was 'net neutrality' for telephones, not actual service to customers. Now it does mean universal service to customers. Telecommunication companies are granted preferential treatment, guaranteed profits, active suppression of competition and tax revenue from the USF. In return, they must provide universal telephone coverage (not broadband or internet), maintain the infrastructure and improve it. Telecomms aren't stupid, so they do the bare minimum in unprofitable areas.
This is primarily rural areas, not necessarily poor ones. Actually poor people can be extremely profitable to certain providers. Customer density is a huge factor of profitability of utility service. Servicing a single town of middle or low class customers is insanely more profitable than say a hundred billionaires that live a couple miles apart from each other.
There is disagreement of how burdensome the universal telephone service is to telecommunication companies. There's less disagreement that over time, it's becoming less burdensome as the infrastructure is built and needs only to be maintained. Though maintenance isn't cheap. Telecomms also claim that competition would defray the compensation from the Service Fund and make the system unsustainable.
You cannot separate utilities from government, because utilities rely on government or public property. Aside from extremely narrow circumstances, it would not be economical to provide any utility without access to public right of ways. That's why "these territorial monopolies" are classified as utilities. If they were economical or even possible without government property, then they wouldn't be utilities.
Internet and cellular services are sort of but not entirely considered utilities. They receive some of the benefits of being a utility, but also escape some of the downsides of being a utility. Again, landline telephone service is "net neutral". AT&T can't charge you extra for calling Papa Johns, or flat out refuse to connect the call, because Dominos paid off AT&T. Certain internet providers want the best of both worlds, with none of the downsides of either world. They want government protection and money, and they want the ability to pick and choose. It's perfectly understandable, as they want maximum profits and minimum liability.
There's no magic answer. Treating internet providers as utilities then puts them into the utility category. While they are forbidden from certain business practices (primarily selective service), they also become functionally immune from any meaningful competition. And government utility oversight often is very preferential to the utilities, as they tend to be compromised of former or future utility personnel. Think Treasury Department and Goldman Sachs. On the other hand, letting them conduct destructive practices against a captive consumer base isn't great either. I'm more partial to a solution that ensures universal minimum service with profitability for the providers, but also makes it easy to allow further competition. But widespread reform not possible when you're talking about thousands of municipalities.
Anyone screaming that one side is pure as new fallen snow doesn't understand the situation. It's a complex situation without a single best case because there's too many parties with conflicting interests and incentives.
