I suspect that most, even a lot of professional users, could get along just fine with CS1 or CS2. The core functionality hasn’t changed all that much and in a lot of ways, CS/CC apps have gotten worse. The only reason these individuals aren't still using those old versions is because they aren’t well suited for modern machines.

I’d personally be elated if Adobe started selling a lightly modernized single-purchase Photoshop CS1, even if it cost what single purchase PS licenses used to. The lack of cruft and UI churn alone would be worth it before even getting into the savings compared to a subscription.

The Mac version has lived through 68K MacOS pre and post System 7, PPC Mac pre and post OS X, x86 Macs pre and post Carbon support and now ARM Macs. After each transition , there was a limited amount of time that you could use the same version and even a smaller amount of time that you would have wanted to.

But the same argument applies that applies to Figma. It’s a professional tool that should help you generate income far greater than the cost