Mickey Mouse Copyright Act claims all recordings until 2067

I've written before about the ridiculously-long terms on copyrights under current law, especially the Sonny Bono Copyright Term Extension Act of 1998, seemingly created specifically to keep Steamboat Willie, and therefore Mickey Mouse, from going into public domain. Now this, from Megan McArdle:

Sound Recording Rule of Thumb: There are NO sound recordings in the Public Domain in the USA.

Records, cassettes, CD's, and other music recordings come under a general category called Sound Recordings or Phonorecords. The publication of Sheet Music placed a song or musical work under copyright protection. Sound recordings, however, were protected by a hodge-podge tangle of state laws, but were not covered under Federal copyright law. It was even determined that there was no federal criteria to actually "publish" a sound recording. This was fixed with the 1972 US copyright act which officially "published" all sound recordings in existence on February 15, 1972, and 75 years of copyright protection was enacted for essentially every sound recording created in 1972 or earlier. (1972 + 75 years = 2047). The Sony Bono Act of 1998 extended all copyright protection an additional 20 years. Therefore, the earliest that copyright protection will expire for any sound recording in the USA is 2067 (2047 + 20 years = 2067).

Emphasis added.