I think spreading those kind of lies[1] if a part of why there is a divide between the W3C (at least the RDF community) and the rest of the word. The W3C should be more transparent about RDF capabilities and realistic about the real power of the Semantic Web.
[1] this false because RDF use IRIs not URLs, and not all IRIs are dereferenceable. Moreover, even URLs used as resource id are not constrained to be dereferenceable per the spec (and when they are, you'll get a lot 404 in practice). Also, the same effect can be obtained as easily with properties (key value pair) attached on nodes of graph database.
That has been one of the main motivations why I've been working on a content-addressed semantic data/ontology format[0] with a modern decentrelized stack in mind.
Thus, if someone is looking to unify graph QLs that are in actual use in "business" problems, SPARQL and the overall RDF aren't going to get attention. You can start with the fact that RDF basically assumes you want to globally address all your data with URIs, which will result in ridiculously verbose overhead in naming/addressing. Nevermind the fact that such things basically promise some sort of long term durability that the actual web has shown doesn't exist. After all, today's URI link to URI www.tla.com/link/to/some/data can mean the world wide wrestling foundation one day, and the world wildlife foundation the next.
In particular, Gremlin was adopted by DSE / Titan / successor to Titan which ran atop Cassandra for near-limitless scalability.
RDF and the Semantic web, while being intended for the massive WWW, seemed to not have any care for demonstrating techniques, queries, and architectures at scale.
Likewise, are Datalog and Prolog used extensively?
URIs and RDF in general don't need to use public HTTP links or anything like that, meanwhile the layered systems like OWL and RDFS provide some impressive features for implementing complex systems, especially when you actually want to use a semantic graph instead of loosely-schemed bag of nodes and vertices common in non-RDF graph databases.
It's just not getting the "kool" looks and gushing reviews, mostly written by people who totally missed all the previous research. Which is a common problem all around in computing.
Also, much of the work in validation (SHACL, Shex) of graphs leverages SPARQL so it's not going anwhere soon. I would like to see it evolve to allow more vertex based searches without the need for extensions though.