As I've now learned, you used to work for the Internet Archive. You should probably start your statements with that.
> If you've taken no self-help measures to limit access...
robots.txt was a nice self-help measure.
> ... then bad actors, unobservable to you and regulators, will still be doing whatever they would like to do and can get away with.
Regulators still have to follow regulations. You are right that I can't stop someone from creating offline archives - but they're not really who I am worried about. Nor am I worried about the small servers that keep copies of documents during transmission, unless of course they're doing so for criminal reasons.