For my part I pay for services that offer value to me, and don't pay for those that don't. I'd rather subscribe than getting harassed with ads and popups. The people who put the effort into creating useful services shouldn't have to live off charity.
Keep in mind your product may have a varied client install base of Windows 10, Windows 11, Mac OSes, possibly various flavors of Linux as well as mobile OSes as target platforms. I guess depending on your product, maybe you build and sell a self hosted server option? In that case you have to think of what server OSes people could be running and figure out a way to help those customers install, configure and patch the software you'll sell to them. Running things in the cloud and with containers is fairly common so you may want to look at creating container images customers could use and ways for them to keep their data when you roll out new versions.
You'd of course want some really good install documentation for people to start with first. Then you'd need to staff up support people to help customers with installs, patches, upgrades and security vulnerabilities in the stack.
The key word here is "service". This is what most subscriptions are addressing.
What would a viable "solution" to service look like? Self service perhaps? Or maybe no service?
Have you considered that "self service" and "no service" are options that subscribers have already specifically chosen to avoid for reasons that are perfectly logical and valid to them? Just unsubscribe and say "no" to service is not a universally viable alternative.
This seems akin to looking for a solution to "food" or "water".
Who exactly is forced into subscription software? If you don't want to pay for a subscription then use something open source (maybe consider donating or contributing), paid up front or write your own.
This feels like a particularly HN obsession, like complaining about Electron being part of everything or wondering why people pay for software in the first place when open source alternatives exist.