That's basically a variant of a subscription, but one where the end user churns aggressively.

It's worse in many ways too - it's a lot harder to gauge interest as the developer to understand how well any update will sell, and if the updates "stack", then a user only pays for the newest update to get all older features free. It's also worse from a cashflow perspective for the developer (but better for consumer) since they have to pre-build the update before any chance of getting paid for it.