Indeed, that was attempted, but it was vetoed by the judge:

https://en.wikipedia.org/wiki/Authors_Guild,_Inc._v._Google,...

Furthermore, there's a fair bit of pushback by many content creators around orphan works legislation. This has been perhaps most pronounced with photography. There seems to be a concern that big corporations won't try very hard to reach people who have neglected to renew copyrights and will snap up their works.

(Not saying I agree with this POV but it's out there.)

>people who have neglected to renew copyrights //

Renewal, indeed registration, is largely a USA thing since the Berne Convention (adopted nearly everywhere before USA signed in 1988) did away with the need for registration in the 19th Century.

Worth bearing in mind, the USA as with "English" measurement is a good step out of line with the practice in the rest of the world. Any argument based on someone not registering is going to need completely rethinking outside USA.

Fair enough. There have been proposals to make copyright terms shorter with renewal options but those aren't inherent in orphan works legislation.

In general, I favor orphan works legislation but there is both potential for abuse and ambiguity in how much effort will and should go into tracking down rights holders.