That is maybe a good idea! If I were going to do it, I'd start by crawling AllMusic and select portions of Wikipedia. But it's easy enough to do it manually for the use case, "I've run out of stuff to listen to by X, how do I get more?"

I had attempted to do this four years ago but had hideous experiences with trying to find someone to assist me with execution.

When I was working on it, it seemed a lot simpler to query the Musicbrainz API for a lot of the information.

I'd like at least some graph database containing all these entities. Can probably be scraped from the internet, would need to know which ones are highest quality and most comprehensive though.

what you are looking for is MusicBrainz. You can download their full db and start hacking from there.