Re: 'making Google's vid-hosting platform liable for infringements on copyrighted material would'
It is up to Google/Youtube, Facebook & Co. to come up with a method for pre-clearing content (E.g. YouTube "stars" can pre-declare that the content they are uploading falls within the law and the content is theirs alone or they have the electronic rights to distribute the material.
Maybe some sort of digital certificate from the content producer - if they want to ensure they get paid, they have to do some work as well and issue valid, traceable digital certificates, which the uploader attaches to the video. If the copyright holder then see a misuse of the content, they can revoke the certificate and the video will be automatically "pulled" on all services that use it.
The uploaders could digitally sign an afidavit that the content is theirs and they have the rights to upload the content. Of course, it would mean uploads over anonymous accounts would have to still be vetted. But "legitimate" sources (podcasters, Youtube stars, influencers (yeuch, what a horrible word!) etc.) can ensure that they are taking responsibility for the upload and their videos can be uploaded straight away or just subjected to random sampling.
That is just a couple of "simple" ideas off the top of my head. The idea is simple, how easy it would be to implement is another idea, but YouTube and Facebook have earnt billions from "illegal" content over the last decade, so the funding for implementing a scheme has already been, illegetimately, earnt.