One could argue that MS Office and Adobe products were always "subscription-based", if companies and professionals never left the update treadmill. After all, if all you need is MS-Office 2000 or Adobe Photoshop 6, no subscription is needed and you can still find licenses around.

One could argue it.

But they would then have to answer why would non-business buyers, that is, users who did "leave the update treadmill" and bought new updates (or skipped them) at their convenience, suffer the subscription model too?

Because they are such an irrelevant part of the market that they basically could disappear and no one would care, and the hobbyist/non-professional people who don't mind using years-old software could as well just use Free/Open alternatives?

There is nothing stopping Joe-who-only-pays-full-licences to continue using his MS 2007 Office suite, is there?

Os support, especially in the Apple world.

It's not merely "especially in the Apple world" - very little in the way of older Windows/DOS software still works today (unless you're also running old/unsupported hardware (subject to its own foibles) and operating systems

Products get deprecated/go out of support all the bloody time - there is nothing wrong with that: should Ford have to "support" the Edsel or Model T today "for free"? Why?

The only thing I don't like about subscription is rent-seeking. I'm fine paying a small amount every month if I expect security updates or small features that won't impede my workflow. If there is a lot of request for additional features, you can always bump up to a new version. If there aren't, that means your product is mature, or you may need to market to a different segment. But I'm not paying you every month just to shuffle the UI around or to be able to access my data.

You don't get to decide what is "small features" and if you start fragmenting software into multiple releases you are going to make it more expensive for everyone, because now the company is supposed to maintain N versions because you are a special snowflake.

Or you can sidestep the whole thing entirely and use/fund/ promote Free Software. Your "small monthly amount" will go a long way and you will be free to pick and choose as you want.

Right, which is yet another explanation of why companies moved into subscription-based models: unless you are willing to be frozen in time with all your software tools, you will be in the update treadmill one way or another. Bitrot exists, and someone needs to pay for it. A license you paid 15 years ago does not (and should not) cover that.

Isn't a big reason for this development precisely that many didn't pay top dollar? There used to be a lot of Photoshop, Windows and Office warez floating around.

I suspect most of the piracy in those apps was among people who were never the target market. Someone who wants to make funny cat pictures, or even edit photos they took with their $300 point-and-shoot camera isn't going to pay $400 for Photoshop.

Professionals who make their living using Photoshop usually don't have much trouble with the cost, whether paid monthly, or occasionally when a new version has a feature they care about.

Being able to bring in some more casual customers with a lower initial cost is just a bonus.

No, since that's orthogonal. You can pirate with or without a subscription.

Well if this isn’t the pot calling the kettle black. You raise the statesman that I said people claim software should be both free and maintained indefinitely. I did no such thing. I merely asserted that it should not be.