I don't know. We had a pretty well established model that included free updates, but required a new purchase for a new major version down the line. I think that worked pretty well.
> The license entitles you to receive lifetime updates for the major version. When we release the next major version, you can optionally renew the license.
Fairly common. JetBrains started that way too. Will they one day have a major version that's using a subscription model? Perhaps. But they will likely not regret this too much.
Insert some convoluted argument about new versions being "new versions" and not updates, so one is not entitled to them ;-) , just like politicians argue things like genocide not being genocide.
I hate the subscription model but I do recognize if they continously update the software, they'd like to get paid to do so.
I suspect the vendor is going to regret that, further down the line.