Agree with the point about SemWeb. AFAIK, RDF/OWL/SPARQL is kindof a long-term pet project of TBL's, and now with SOLID IMHO he's kindof reusing parts of it as a 2nd chance to finally become mainstream (with weaving and creatively interpreting specs as is typical of SemWeb). What SOLID wants to achieve, though (a federated, less centralized web) is too important an initiative to let it become a case of puzzling out an utopian stack based on tech that has failed mainstream adoption, so unfortunately can't be taken seriously, and seems more like a project for fundraising TBL's pet project. Saying this as someone who has just recently worked with SPARQL and graph DBs in bioinformatics which is one of the domains where it actually has gained traction.