To put this really bluntly, these companies would _prefer_ that kind of system. Right now the problem is that they are held legally liable if they incorrectly

To put this really bluntly, these companies would _prefer_ that kind of system. Right now the problem is that they are held legally liable if they incorrectly reject a copyright complaint (which, by the way, can only be determined to be valid in court) but only run the risk of pissing off users if they accept a fraudulent one. The problem here is not convenience, it's that copyright was designed for an era when it was kind of hard to copy things. The DMCA was a good shim to make it feasible for Internet companies to even exist, but it's not enough to fix things in a world where literally every single bit of IP can be copied or downloaded in less than a day. If, for example, Congress required content owners to submit copies of their works to some centralized US copyright database as a condition for being eligible to receive damages from platforms, that would go a long way to fix things on its own. Expanding the explicit set of fair use exemptions and allowing them to matter outside of a court would also be a big help.