This seems very well reasoned. Ultimately what I think will win is whatever abstraction popular ORM providers can make easiest for devs. It might be ‘wrong’ to

This seems very well reasoned. Ultimately what I think will win is whatever abstraction popular ORM providers can make easiest for devs. It might be ‘wrong’ to treat vectors as a related table to your main model, but if frameworks and ORMs make it easy to handle the downsides of that abstraction in the app layer and a dev can just have one database for everything I think that will be the most common approach.