> SemWeb stack has almost zero adoption since its inception while graph databases are trendy

Where is my LOL GIF :D

RDF Knowledge Graphs used by: Elsevier, Bloomberg, Thomson Reuters/Refinitiv, Uber, Zalando, Microsoft, Apple, Amazon, HSBC... do I need to continue?

If you mean "mainstream developer" adoption, that is a poor and irrelevant indicator, because mainstream is not where the innovation happens.