[robocat]

> Taking an established, OSS project and closing it destroys that community

No. If there is a vibrant community of developers, then that community can make the decision to fork. From the OP it seems like there is no community, just enterprise users that do not “give back” open source, which happens.

Even without the community, those enterprise users can create a new community of users to keep the current version maintained.

A similar situation occurs when a library supplier company goes under - which is one risk you take on whenever you depend on a commercially developed library (whether FLOSS or closed).