Big hit songs are hit with copyright infringement claims over vague similarities to other songs.

I think this is a sign that the criteria for infringement are too loose. But it is also a consequence of the increased practice of songwriters' or their heirs' selling their whole catalogs to companies. I speculate that they are using AI to search databases of thousands of songs to find opportunities to sue.

Copyright lasts far too long. A 1973 work should not be copyrighted today.