To be clear, I appreciate the concept of an "Internet Archive", but the current organization / execution / management is absolutely atrocious.
Suppose it were significant; then how many of the artists' descendents are getting their share of the streaming revenues on those copyrighted trax? (Before the copyright expires, of course.)
Another specious claim of the majors: these trax are 'still out there'. All 400,000? How would you know, and how would anyone where to look? If you can find where they're hiding, one at a time (online or in a cardboard box under a table in the back of a record store in Poughkeepsie?) Here they all are, on one library's website.
The Great 78 collection is a wonderful and delightful addition to the historians and explorers of 42 genres of music. It's the sort of contribution only a Great Library could afford to make. Of course, beyond the comprehension of mere commerce.