Hmm. The argument seems to be that pre-1972 sound recordings (only recordings, not compositions) enjoyed protection under a patchwork of state laws and aspects of common law, protection that was arguably unlimited. (It's not clear to me whether these are technically considered copyright protections; I guess not.) Therefore, protecting artists' right to receive royalties from streaming, as long as the performance is still under copyright, isn't technically an extension; in fact the 2067 cutoff could be considered a new limitation.
So I guess my take on this is that I still feel that copyright terms (95 years or longer, depending on certain circumstances [0]) are too long, and I can see that this bill might technically not be making the problem worse.
http://www.copyhype.com/2018/05/no-the-classics-act-is-not-a...
I'm hardly a fan of copyright, but the arguments that this is not actually an extension seem sound.