That's the way the music (Pop, Rock, Rap, ...) world works anyway.
The Classical musicians are struggling, so they turn into Rock music because the money is better coming from the kids filling the football stadiums.
We could write a book about that...
Led Zeppelin is big, very big. These guys are doing very well financially today. ...Metallica too.
But it's like painters; the first creators when they get recognized it's generally too late; they're dead, and they lived a poor life.
But some wise folks will take advantage (very natural) and copy some of their stuff, style, riffs, words, ...to cash in.
None's wrong with that; they simply don't have the same level of creativity as the originals. But it don't matter; what does are the kids who like it and pay to see it and hear it, us.
I don't know how it will turn out in court, and what the judge will decide. May the best win, and justice done for all.
Money motivates, karma follows, and heaven knows.