That's what governments already do.

https://www.copyright.gov/mandatory/

> All works under copyright protection that are published in the United States are subject to the mandatory deposit provision of the Copyright Act (section 407 of Title 17).

> This law requires two copies of each work published in the United States be deposited with the Copyright Office within three months of publication. Works deposited under this law are for the use of the Library of Congress. Usually, deposited copies must be the “best edition” of the work, which means they must conform to the Library of Congress’s preferred specifications.

> Mandatory deposit applies to any work published in the United States. This requirement does not apply to works first published in a foreign country until they are published in the United States. Copyright registration is optional, but it provides additional legal benefits and fulfills the mandatory deposit requirement with the submission of the required copies.