> have to keep paying regardless of whether you want or need any of the features being introduced
This here is the misunderstanding. A better way to phrase it is that you have to keep paying if you'd like the software to work.
On most platforms just keeping up with the OS and library changes requires plenty of work and it is unreasonable to expect someone to do this without constant income.
Now, when I'm a customer, I see things differently: if I use the software and I intend to rely on it, I want the developer to survive, so that they can maintain and develop the software in the long term. Paying a one-time fee will not result in a sustainable business, so the software will eventually die, disappear, or get acquired, none of which is good for me.
Downvote me all you want (HN can be really narrow-minded at times), but when I look at new software that I intend to rely on, one of the main things I consider is whether the developer has a sustainable business model. If they don't, I don't want to invest my time into learning, migrating to, or integrating their software.
Incidentally, I've been running a solo SaaS business for a number of years now. It's B2B only. Seeing the knee-jerk downvoting reaction here only convinces me that not providing any B2C plans was the right choice. I just give my service away for free to hobbyists.