>> While Unreal engine currently does not have terms like Unity’s, there’s nothing stopping them from doing something similar. In fact if Unity manages to get away with this it seems likely they will follow suit. Unreal has licenses which allow you to use one version of their engine FOREVER and they cannot revoke that license. So the author didn't fully research this. It is true that for NEWER version Epic can change…
Isn't that valid for any software including Unity or Unreal?
With open source at least you can try it yourself