I will never understand the appeal of subscription music services.
Spotify has enabled a degree of discovery and curation that is simply not possible for anyone without access to an insanely good record store and/or really, really deep pockets. I cannot imagine any reason to ever go back. If Spotify ever goes under or removes an artists I really like, I can always buy it then. But until then, I will happily pay my $10/month and keep using Spotify as my sole source of music. Frankly, I think Spotify is the cheapest thing I have ever spent money on when compared to the value it provides.
Even if I could afford to own all my Spotify music, I would have to be responsible for backing it up and moving it between devices or into the cloud. So I would get less value for 10-100x more money. And this figure isn't even counting the value of the discovery service that Spotify provides. If I meet someone from halfway across the world, I can ask for musical recommendations, and then listen to them in my car on the way home.
Honestly, I don't understand how you can seriously explore music without Spotify.
Then I bought a CD player and started building the collection again. Not surprisingly, the new collection contained different stuff. Not much at all overlapped with the old collection. When I moved, I didn't bother bringing the tapes (or the records that preceded them).
Now I have a pretty good collection of music on .mp3. Some of it is ripped from those old CDs, but a lot less than you'd think. Those CDs are in storage, somewhere, I think. Every once in a while I find a stack of them and do a kind of "yeah, hey, It's the motherf'ing D.R.E... Those were good times." before putting them back.
So I think the idea with subscription services is that they handle the case where your tastes change. If I were the king of guy that really wanted to keep blasting the same Judas Priest album that marked music's perfection back in 1987 today, I could see the point of hoarding music.
But then I'd probably need to go find another black Trans Am (yes, with T-tops & screaming eagle on the hood, just like the Bandit had) to blast it from.
Times change though, and people move on. For a guy with $10 a month in his pocket and the ability to put pragmatism ahead of sentimentality, streaming music services actually do make a lot of sense.
To me the idea of owning music is tied to the need for physical media, which we don't have any more. We don't worry about owning TV shows for example because they weren't traditionally broadcast that way.
Of course, this ignores the fact that there's no way I could have discovered all the music I listen to without Spotify. Even if I knew of all the artists I listen to on Spotify, I could never possibly have found all their music in physical form. And if I had to purchase all the music I listened to separately, I never would have been willing to explore so much.
But still, I fuck around with streaming services (the ones that work here in Japan, anyway) as a way to explore newer music -- the best of which ultimately ends up in my permanent collection.
You can do both.
The media server can run on Windows, Mac, and Linux, so I have it set up on my web server. You can then use a client on Windows, Mac, iOS, or the web browser to stream music, photos, and movies. You can also share your library with other Plex users, so if you have libraries that are always online, consuming media from iOS for you and your friends can feel very much like your own private Netflix (and Rdio/grooveshark)
It truly is the smoothest way to stream your own media, I've tried them all.
Before Cloud Drive, I used Subsonic, which is self hosted. Though it never really worked all that well.
I do have the same intuition that you do that subscription music services are unsatisfying, but I think the line is starting to blur. I use iTunes almost exclusively as my music library, through iTunes Match and my own iTunes purchases. Other than the songs that happen to be cached on my devices, this is not physically any more permanent or "owned" than a subscription service like Spotify. Granted, I can download and backup music from iTunes, but that's an additional step that most people presumably don't do. (I do keep fairly recent backups of my music, and much of my especially cherished music is backed up from CDs, though I refuse to purchase physical media these days.)