Some developers are seriously considering de-listing their games from online shops when the Unity Runtime Fee kicks off at the start of next year, meaning some titles built on Unity could end up being temporarily — or permanently — unavailable. Here's what developers are saying about the Unity Runtime Fee on social media, and what games could be impacted.
This is a far more nuanced situation, but even in what you’re describing the service is then ceased, you don’t get to continue using the service on the previous terms.
I’ve seen a claim that the old terms of service explicitly stated that you could do so so long as you didn’t update to the newer version. Which is probably fine for most developers who are already deep into a Unity project. (Though as Unity has now taken down their GitHub page with those terms on it, I haven’t yet seen anyone link to an easy to verify and read copy for people to see if that’s true or not.