If they don't want to maintain the copper lines, they can always replace them with fiber.

Pretty sure the Californian authority is not a copper DSL religious cult. If you actually read the article, the regulations they are citing are built for vulnerable communities to protect them from for-profit utility providers from cutting them off by shutting down old but only available way to provide internet to the people.

Wireless is not a fix-all solution, and can be unreliable and bandwidth limited for dense areas.

This message is sent to you by someone whose utility provider decided to do exactly what you wish and now is stuck with wireless towers that completely go down if there's any heightened usage (tourism, people moving in, and so on) or pretty much randomly (and since the infrastructure is not built yet, the company's nearest branch is nowhere near me), if you move too quickly, go to a room the tower doesn't properly reach (yes can be fixed, but now the burden of cost is on the person not the company), and many more issues that arise when 'wireless towers' are provided instead of actual internet cables that might be slower, older and more expensive for the provider but much more reliable, stable and actually working most of the time.

Wireless as the only option is a fucking joke.

I barely want to use WiFi at home let alone send it to a tower far away. This reminds me of those stupid 5G home internet plans you can get — why on earth would I want to add so much latency to my internet connection?