https://www.techdirt.com/articles/20200220/09561543951/attempt-to-put-every-musical-melody-into-public-domain-demonstrates-craziness-modern-copyright.shtml

The fact is that many of the copyright lawsuits we see coming out of the music industry mostly revolve around copyright claims on musical melodies. In many of these cases, artists find themselves on the losing end of judges and juries all while claiming that there was no intention to infringe, with the supposedly offending material instead being developed as essentially an independent creation that happened to be similar to previous works. The Blurred Lines case went that way, as has the Dark Horse case. The problem with this is that music is somewhat akin to mathematics, in that within a given octave or set of octaves, there are a finite number of musical combinations between notes that can be made. Sure, that number of combinations is large -- tens of billions, actually -- but the finite number of resources exists nonetheless.

Given that fact, affording copyright protection to melodies like this is absurd. The entire point of copyright law is to promote the creation of new and original works. If copyright law itself is to be applied such that on a long enough timeline no further works can be created, assuming artists can create music fast enough for all musical combinations to be copyrighted, that is the literal antithesis of the point of the law.