[kemitchell]

No well-known permissive open software license includes any promise to do future development, much less to make it available under the same license terms. A key draw of permissive licensing is that anyone can fork and put new work under new and different terms.

Who would promise perpetual maintenance for nothing? What organization would sign up to be the only one that can't change terms for improvements?

I don't think "social contract" makes sense here. There's no sovereign power involved. In the sense used, "social contract" essentially means "not in the contract"---as in not in the terms. It's a back door for saying things that were never put down ought to be treated like they were in the license file, just because one side really wants them and doesn't want to DIY or pay for them.

If there are disappointed expectations, that's another thing. But being even very disappointed, and being able to find other like-minded people who would prefer no disruption and new freebies forever, doesn't make unfounded expectations enforceable, nor should it.

I'd be extremely careful speaking of any singular "community". And of assuming that everyone in it expected Redis or another similar project to work just like Linux or other exceptional projects. Most devs dealing with open source have a project relicense---among many others than simply grind to a halt---at some point in their career. For some devs, Redis may have been the first. Others "adopted" Redis knowing the risk and accepting it.