Given "there was a time that subscriptions for software were virtually unheard of", it's safe to assume we're talking about more than a couple of years ago. To talk as if most users always used to upgrade, suggests you might be young enough not to remember the software industry before a decade or two ago.

In general, users very much didn't upgrade. That's exactly why the industry forced subscriptions on us. They weren't getting income anymore, when the older version of their software did the job perfectly well.

With subscription,the only thing certain is that the seller wants to do as little as possible to keep taking my money. This tends to result on product updates that benefit them.