Hey @Scott_Johnson1 – I saw your previous post and the one above, so I split this out so we can look a little closer at this.
First off, your collection sounds a lot like mine 
As I’m sure you know, the common thread for a lot of these genres is that they largely originate with vinyl releases. The sources we currently use in Roon (AllMusic/Tivo, and MusicBrainz) have pretty great coverage for lots genres, and the data tends to be deep (meaning it has credits, composition info, release information, etc), even if it’s not always as broad as I would like.
These sources also tend to favor CD releases, particularly those from the US. It’s hard to be sure without specifics, but I would guess these are all contributing factors for the poor hit rate you’re describing here.
As you mentioned these kinds of releases often get better coverage in Discogs, and we are hoping to add Discogs data to our metadata infrastructure in the future. It’s a slower process than we would like, but it is something we are actively working towards. I suspect you’ll see a lot more “hits” once that data is part of Roon.
For now, I’d be happy to look into this a bit more for you. Information about releases you would expect to hit but which did not are interesting – if those albums exist in MusicBrainz or AllMusic, even more so. The nice thing about Roon’s metadata is that it’s always improving in the background as new data is added, bugs are resolved, and your library updates.
I too would like us to do better with collections like yours (and mine) so thanks in advance for the feedback.