Assuming copyright was dissolved it wouldn't be a huge money maker for the recording industry (questionably legitimate money receivers) or the artists (definitely legit) it'd be a huge money maker for apple and spotify that'd harness all that uncopyrighted stuff to make money on.
How would it be a huge money maker for Apple and Spotify when anyone else can provide the same content, driving the cost down to the minimum required to cover the hosting and bandwidth.
At that point it'd essentially be like a book repository and while there are several big open book repositories (shout out at mek) the demand for daily consumption of those isn't there in the same way that music is consumed. I can't say for certain but I suspect we'd essentially have something that looks a lot like the search engine wars - some minor players might strike it big - but Google, Apple and MSFT would all present options backed with a lot of cash to try and dominate the market. It'd all be about the algorithm to deliver the data in a pleasantly suggested manner - and companies that could offer value here would rake in loads of money with the mobile device offers locking down their devices to dissuade users from seeking free alternatives.
How did it becoming a huge money maker for people who already have way too much change your views?