The amount of music you own has 0 bearing on your knowledge of video game music. You could have gained knowledge anywhere else -- existing, well documented vgmdb.net entries; YouTube streams; downloaded media; discussion on forums; Owning an album doesn't give any more weight to someones opinion at all. The only thing it shows is you have a vested financial interest in the hobby vs. someone who just downloads or streams. That's it.
I would agree that the relationship between how much VGM someone owns, and how much knowledge someone has about VGM, is very weak at best. I would also point out that the vast majority of all VGM has never been published as a soundtrack, and thus can't be collected or bought by anyone.
And to keep building on this... a 10,000 album collection could contain
~ 15x Every Final Fantasy album released: 678 albums
Well, Rrolack has also been buying a lot of doujin/indie/cover albums which are easy to inflate your count. It really depends on who you are talking to because I know some people don't consider that part of VGM collections because they're not commercial produced soundtracks.
It's a good question as to what "counts" as a collection. For example, Amazon.co.jp obviously has a lot of albums, maybe even 100 copies of some albums. So should a store's inventory count as a VGM collection, or not really? It seems like the answer is "not really" if we're talking about a corporation like Amazon, but how about an individual like otaku or champs_de_pins? They might consider themselves to be both a dealer and a collector.
What about digital albums, both free ones or paid ones? If I download 10,000 free VGM albums from Bandcamp, do I then have an enormous collection?
When I asked the original question, I'll admit that I wasn't thinking too specifically about what is and isn't a collection. Though if I were told someone had 5,000 albums, I would think it was much more interesting if it were an individual collector (not a store), physical albums (not digital), and not 5,000 copies of the exact same album