Thank you so much again for your replies and feedback @NoelDeMartin and @timbl !! 
1- Using MusicBrainz as a starting point to retrieve public data would be a great idea. MusicBrainz provides JSON-LD format with their API, so the Linked Data objective wouldn´t be missed for a SOLID approach as @NoelDeMartin mentioned Music Platform - #17 by NoelDeMartin
" […] it could be a Solid POD with public indexes listing artists’ WebIds"
It’s also beneficial to engage new comers to select their favourite artists and from there build their music taste. On the other hand, I don’t see this idea really compatible with a public repository of songs, as in @timbl (https://timbl.com/timbl/Public/Test/Music/). I don´t know to what extent the public hosting of copyrighted music can derive into legal consequences. I don’t want to greet a bunch of lawyers at my doorstep after my first commit 
2- I agree with @NoelDeMartin in “the intention is that artists upload mp3 to their own PODs” and make them available to anyone (logged in or not), or just the audience they want to target . Thanks for sharing Funkwhale , I´ll definitely dive into it!.
3- With regard to the market I have my concerns and this also connects to a previous comment from @ThisIsMissEm Music Platform - #3 by ThisIsMissEm “musicians usually want to be paid for their music”. Well, sorry for the off-topic and making it personal, but when I started thinking of this platform, some time ago, the challenge was not exactly the business, it was the technology though. I wanted for music the same principles I like from software, openness and collaboration. A concept like SOLID is what I expect (as a geek) from a tech company focused on independent music (i.e. Jamendo). I can give you more details about future plans on how and why it could be worth it, but it would be out of the scope of the really exciting part which is actually building it!
PS. I think Projektor can be a good example also and starting point except for the public willingness