Or is SaaS just an exploitative business model that's bad for customers but good for software vendors?

Yes, that's exactly what it is.

The good news is that there's absolutely no software I need. I have great image and text editors, many other tools, great development systems and numerous languages at my fingertips, VM(OS)'s and their tools running under my primary OS, all locally. Many of my own creation.

I can stay with this until my hardware dies and I can't find a replacement on the used market. Something I don't think will happen until long after I die.

And the web/network and its constant churn? Or some threat that they won't address in the OS or VM(OS) I use? Well, fact is, I'm retired. If I have to abandon the net because they've turned it into something... else... or it's untenable for some other reason, well, so be it. I was fine before the net arrived, and I'll be fine without it later. I do not need "the latest thing" to be content and creatively engaged. I'm off that train, and have been for some years now.

Too bad about the rest of you though. They really have you by the short hairs now.