You might not "own" it but in the state they sold the rights to you it gave you a fair amount of control over what you did with it. Even on iTunes you can burn a CD and move that media around freely without internet. Re-rip the burned CD back to the computer and you had DRM free music. In my car for example I listen to MP3s on my phone because then I get the best quality and don't have to deal with the faults of cellular service. I have 256GBs of space on any given phone and an extra 64GBs on my Note8 so its more than enough for me to carry around my favorite music and more.You never own the music. Just the right to play it. There's value to having virtually endless access to data without needing local storage space.
And obviously consumers find more value there, than they do being able to stack their CDs up in a room
The value consumers find in streaming is the price more or less. Streaming was priced so cheap why wouldn't they prefer it? The companies that sell streaming services want you to see it that way because when they stream to you it gives them far more control over the end product. If it cost $1000 a year to stream Spotify do you think people would have still gravitated to services like that over paying $10 per physical disc? Nah.