Cross-referencing is happening on Wikidata, see https://www.wikidata.org/wiki/Wikidata:WikiProject_Music

I hope that the genre graph/improvements you mention here and https://some.gonze.com/2016/06/29/open-genres/ eventually get developed in Wikidata as well. But this is mostly an idle hope that Wikidata and facilities built on it will help build better graphs than those that fall out of Wikipedia categories.