No space mosh-pits, but we do have a plethora of mobile music streaming apps on our phones [Top Mobile Music Streaming applications [The Age]].
They don't have all-music-ever, but some of them have a large cross section of most-music-you'd-want.
This sort of thing has only been possible due to the massive restructuring of the music business helped along by mass proliferation of cheap fast internet.
Part of that restructuring though has meant many high profile artists are no longer distributed or associated with the "big" record companies. As such, their tracks are often not licenced to these music streaming companies.
Thanks to the internet, I'm aware of, and able to purchase, music from European, Asian, South-American, and obscure American artists that don't get publicity in my country. I tend to use those artists as my check when I look at something like Spotify. If the artist isn't there, I can't trust them to have the music I want, so I don't sign up.
I've yet to find anything like the all-music-ever model I want... except YouTube, supplemented by the official websites of the bands I like.
Regardless, my main problem with subscription music is that I see it as a fundamental shift in my music consumption.
If I start paying to access music as streaming instead of buying music on CD or digital copies of that music, I suddenly lock myself to that business model. I don't want to pay for CDs when I'm already paying to access that music via subscription. Then, if that subscription service doesn't have the music I want, do I wait for it to have that music, or go buy the CD, which I would have done anyway previously?
I can only see streaming music as try-before-you-buy. That is how I use YouTube now. I hear about music I might like, I go listen, if I like it I add it to my Amazon Wish List, and then one day when I'm feeling particularly rich or depressed I go to that list and buy four or five CDs, either from Amazon or directly from the band if possible.
I can't see that changing much.