A few people becoming obscenely rich is not a good in itself. That is to say, it's not a reason that justifies the music industry existing as it does today. That would be like arguing that it's good (just in general) that smoking is banned because I specifically don't like smoking. A good reason could be that it causes more music to be made, or better music, or it lets more people make music. I honestly have no idea if that's true. Certainly the last one isn't; what lets more people make music is access to technology, not the possibility of getting rich.