B went on to do the same to many other small content creators, because B has 100 million dollars in the bank.
Scammers are also extorting money from Youtubers using this feature of Youtube's claim process. See: ObbyRaidz
* Make (big) platforms provide APIs with which rightholders can check new posts for their copyrighted content and request either removal or monetisation
* Give uploaders 48 hours to contest removal requests before they are honoured, during which their uploads stay online, but may be removed from search results
* Once an infringement is identified and not contested, all earned revenue goes to the rightholders
That's rather sensible. However, it was voted down in favor of just making platforms legally liable for all uploads. https://juliareda.eu/2018/09/copyright-showdown/ (The "EPP group" proposals won – that's the Parliament position, not to be confused with the Council's, which are yet to be fully reconciled).
The big problem is to get the majority of voters on board.
Agreed, but here's one that agrees with you :-)
The process might work like this: A publishes something, gets revenue from it. B claims copyright. YT suspends payment to A until the issue is settled. When B turns out to be right, B gets all the withheld revenue plus however much YT already paid to A, either to be paid by A, or to be withheld by YT from other payments to A.