Earlier quoted context omitted.
I havent really seen that many instances where this happens. If you're paying, you also get support - in fact this is a very common structure for open source products where you pay for a service contract. In this case you're paying for them to do it and have the ability to make updates, but since you're paying them to do, they end up doing it.
The situation of interest is when they are no longer interested in doing it or change the terms of the contract under you... which is what is happening right now with Jetbrains. Wouldn't you like to have a way out when they do that?
And if it's really such a problem... then stop using it? I dont know what else to say. What exactly is at risk here?