They could still maintain it by, say, backporting bug fixes. And also accept contributions from people who prefer to stay on the old rug. It is extra effort for them and it is risky (everyone might end up staying on and contributing to the old rug turning it into the new new rug), but that's the price they would be paying for the goodwill.
I am not demanding anything, I am merely exploring if the "license rug pull" problem has a better solution. Redis paid dearly for it (justifiably or not) so if we can find a less costly option, wouldn't it be a good thing? I guess to put it another way, you are trying to change people's attitude towards open source while I am trying to see if there is a way around it.
This seems overly hostile. The comment is pondering if there are alternatives that a corporation could do when switching license that could reduce their "cost" in goodwill.
Stop treating it like they are demanding open source developers do something or are acting entitled because they aren't. They are discussing how, if a project owner wants something (more goodwill when changing licenses), they might do that effectively.
You don't have to think redis should have been handled differently but that doesn't mean you should derail this person's thread.