[gnaritas]

> When first introduced it proved to be far better, in every conceivable way, than the technologies it replaced.

That's not exactly true; what they did was offer a generic query and constraint model that worked well in all cases while offering reasonable performance. They were not generally faster in optimal cases, but they were much easier to query especially given new requirements after the fact because the queries weren't baked into the data model itself. That generic query ability and general data model always come at the cost of speed; always. Document databases have always been faster in the optimal use case.