I mean, in 1999 one of the dominant software distribution models was shareware where frequently applications would stop working after some amount of time and demand payment.
With subscription, even continuing to pay increasing amounts isn't a guarantee than the product will remain available once the vendor decides to cancel it. And, piracy isn't an option for developing countries where the software price is over a year's average wage.
It's never guaranteed, no matter what payment model. There is plenty of discontinued closed-source software from way before a subscription model became a thing that everyone does, and some of it managed to stay alive only thanks to piracy. With subscriptions it's way worse, because it has to rely on a central server, sometimes for no good reason at all, and you can't even do that. It's just bound to happen that the company will pull the plug once it's no longer profitable.
Back in the day, the license keys weren't checked at a central server, there was some kind of check sum or database inside the software instead. This was wonderful for both pirates and legitimate users for when the company disappeared.
I still remember a working Starcraft CD key (though it later turned out that something on the order of 01234566789 worked).
I remember my Windows XP QQWD7 serial key too. Even when central server was the default, there was usually still a way to do an offline activation. Nowadays, not anymore.
Discontinued software can still be usable for a very long time. Proper written applications like Office can work on Windows versions that are decades older than itself, or the worst case continue working on VMs until the end of time, like those legacy apps that are still running from before the 90s.
No joke. It was one of the first apps I used and in non-European languages its leaps and bounds ahead of most of FOSS today that can't even do RTL right, let alone letter merging etc. And doc files work perfectly with all the modern editors too.