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.
The principal difference is that things keep working if I stop paying. All other aspects are secondary.
And generally speaking there is a lot of options that are excellent for developers but complete shit for the users. That's obvious, but it's also off the point in the context of fairness.
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.