That would be one example. What about Redis pulling a license change, and the whole WordPress battle for control?
If it ain't GPL and it IS popular, I think those kinds of things are more likely to happen than not.
Redis has an open fork. Seems "free" enough to me. Companies are not obligated to keep developing the open version forever, anyway. If Redis was GPL, they could've just abandon it and write a compatible clone from scratch. Nowadays, with AI, that even easier to do
Stallman is a real visionary warning us about those risks since de 80s.