I have come to be OK with
some subscription models, but not all.
I think SaaS, and even many platform applications, are OK as subs.
"Buy once" platform app models are subs, anyway. It is unreasonable to expect a software developer to keep a package updated through many new operating systems. Some systems, like MS Windows (and, I suspect -but don't know for sure- Linux), do a great job of retrofitting, so older apps can often keep going, but most mobile systems won't. Apple is in the middle. It supports a ways back, but will deprecate features that older apps may require.
I used to buy the Adobe CS suite, yearly. Each year, I would get an upgrade, as the software would usually get new features that I wanted. I suspect that, eventually, the version I had, would stop working, but I never let it age that long. I probably could have gotten away with reupping every two, or even three, years.
I like the new sub model. I get access to every single Adobe app, at a lower price than what I paid for my yearly upgrades (but more than if I did it bi-yearly). This allows me to do something like install inDesign, if someone sends me an ID file. I don't want to keep the app around, otherwise.
SaaS is basically built around a "service," and "services," by definition, are subs. If I subscribe to a newspaper, that paper hits my doorstep every weekend, until I stop paying the bill. That's an ancient model, that has not changed; nor does it need to.
Hardware is another matter. I can see having a piece of hardware that could benefit from regular firmware updates, but I think it should keep running at spec, with a single firmware setup, despite new versions coming up.
I'm also pretty cynical about hardware that is sold with "lifetime upgrades." It's been my experience that "lifetime," is actually only a couple of years, before the firmware stops being upgraded. As long as the device keeps working with the last firmware, then that's basically what I paid for, anyway. If the device is "time-bombed," though, that's just evil.
If the device works, but uses a SaaS subscription, then I would think that the manufacturer needs to figure out how to keep supporting the device for as long as possible, and have some way to transition the device to “standalone” operation; especially if the company is going out of business, or phasing out support for the hardware. This would probably require legal backing, against corporate officers, personally, as corporations can get off the hook, fairly easily.
Also, I think we should do away with "lifetime" anything. I think the expected lifespan of stuff (like firmware updates and SaaS support) should be spelled out at purchase time, and legally enforced.