When I worked on DEC VMS, the native database was RdB, which was bought by Oracle. They immediately started porting RdB features into Oracle and applying pressure on customers to move over. I think automatic index optimisation was one of the main reasons our DBAs were reluctant to move.
I just checked what happened and was amazed to discover the product is still alive, since 1994! http://www.oracle.com/technetwork/database/database-technologies/rdb/overview/index.html
HP didn’t get people off VMS either, in mission critical operations. VMS was always good for distributed databases because it can do cluster-wide record-level locking in the distributed file system.
I think the Unix version, DFS, died with object brokers and the Distributed Computing Eenvironment, DCE https://www-01.ibm.com/software/stormgmt/dfs/
I’m not angry, just disappointed that we can’t have nice things.