For most people these days, it seems like the answer is that they use streaming services. I would also venture to guess that the majority of my friends seem to use Spotify as their service of choice.
I go back and forth all the time. I have used Spotify for periods of time, I've used Tidal for a while, Apple Music, and also Google Music. Most recently, I"d been using Apple Music, but I traded in my iPhone for an Android phone and no longer had that option.
Because I'd already been paying for YouTube Premium (it's worth $13 to not see ads), I already had access to YouTube Music, which used to be Google music, and I even had an old library there when I used it before.