This is interesting, I've never heard of VMDS before. Someone else on the team may have, but I have not personally. From a quick glance at the linked Wikipedia page, it looks like this was created around the same time as SQL, and therefore has a different interaction model. It also predates a lot of modern version-control software like Git, SVN, and Perforce.

So it looks like VMDS is a rather unique take on versioning data, where data is viewed as objects. Dolt and DoltgreSQL use the table and row paradigms that the majority of modern relational databases use. Dolt is designed to be a drop-in replacement for MySQL, and DoltgreSQL for PostgreSQL, so that already determines the interface. Regarding VMDS' versioning functionality, I see that is supports merging and conflict resolution at the transaction layer, but I'm not seeing anything similar to the concept of branches, which is something that Dolt and DoltgreSQL supports.

Overall, for modern use cases, it doesn't look like they overlap much. VMDS seems focused more on the spatial case while representing data as objects, while Dolt and DoltgreSQL are traditional relational databases that support versioning all aspects of a relational database.