Now maybe, but not when starting up.

Or the random person who uploaded it.

Youtube automatically identifies almost all copyrighted music when videos are uploaded and copyright owners can decide who will be the one to monetize it. Almost all of the major players have the monetization assigned to themselves.

Do you have any data on that? In practice I’ve only seen this for semi-recent top40 major label releases.

I’m referring more to the sheer volume of back catalog older/indie music that users have digitized from vinyl. I’ve talked to several indie label managers who gave up years ago trying to monetize/fight youtube with c&d letters.

This system actually is renowned for false positives and generally poor classification with no recourse for fixing its mistakes. A funny and telling related story: http://www.bbc.com/news/technology-42580523

How do you know that?

There are tons of whole albums which are definitively not "monetized" by their makers.

E.g. old stuff where the band does not exists anymore or all the low selling genres where nobody cares. It is not a bad thing since i discovered a lot of cool stuff like that.

There's some long tail stuff that isn't, but the large majority is.

A breakdown of how the system works (they're trying to sell music for you to use, but it's still a good writeup):

https://www.safemusiclist.com/can-use-copyrighted-music-yout...