If one were to implement it on top of a RDF database then it isn’t any different than a typical backend taking in SQL (or sparkQL) and spitting out json to the client.

People seem to want to fit a square peg in the round hole and then you have servers bucking over a handful of users.

I spent a day or two looking into this when the hype machine was going strong and it’s really not all that bad (with the right abstractions, I suppose).