Usually they release V3 and discontinue support for version 2. Maybe version 2 is somewhat useful still, but it probably doesn't have support for what you need anymore.
maybe the ploy should be to get to V3 as quickly as possible as this pyramid / growth rate collapses or cut costs in V2 (cheaper servers, more efficient code - if possible). This is an interesting thought to me nonetheless.
However, there are some apps that do have a model of $xx for unlimited use, even where there are ongoing costs.
This is sustainable if the app continues to gain new users, hopefully at an accelerating rate. It works like a pyramid scheme where the new users coming onboard subsidise the cost of the existing users.