YouTube does that at great expense and, I believe, partially as the result of a legal settlement, unless I'm mistaken.. Your suggestion would create a one-way ratchet wherein everyone would have to do as much or more than everyone else, in spite of the law or the cost of doing so.

The standard they must adhere to is the law. If this is unreasonable, and law is often unreasonable, the proper response is to change the law, not to ask the courts to create their own standard of compliance that excludes someone who is, by your own admission, DMCA compliant.