I may be talking out of my ass here. But I thought youtube's content ID system was literally only in place because if it wasn't the DMCA takedown notices would be mailed to 1 youtube lane, California or wherever they are actually based. And that youtube itself would be the ones having to respond to the torrent of them that they'd receive.
As such they basically automated the DMCA process being as hands off as possible asking the parties to work it out among themselves or talk to a judge.
The product of all that engineering time is their Content ID system. aka an automated system for issuing DMCA takedown requests.