That's true. But at the same time, the risk is kinda overblown. You can still use the last open version of Redis. There's even an open, community-maintained fork that you don't have to maintain yourself.
Even GPL can't force a company to maintain and keep developing an open version when the company doesn't want to. Even if Redis was GPL (no CLA), they could still abandon it and write a compatible clone from scratch. AI makes it even easier to do
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
If it ain't GPL and it IS popular, I think those kinds of things are more likely to happen than not.