And they also kinda accept the mediocre recommendation (often laden with ads and "place in front" for pay content) which just feels like habit after a while.
That said, I'm no longer using Spotify, and disappearing songs had a lot to do with it. I've been paying for a premium account for some 6-7 years, way longer than I should - it took me over a year to notice that I'm not actually using it, because half of my favorite songs are gone, and whenever I search for something particular, half of the time it's not there (or worse, there's some shitty cover of it). And it's not just the catalog that suffered since - also the UI of their mobile app rotten over time, and became incomprehensive.
But back in ~2012 - 2015 I sure as hell was happy with their service, and evangelized it to all my friends, and I did feel it's worth more than what I'm paying for it.
I guess losing music on Spotify isn't that big of a deal for most people, because - extrapolating music-related behavior from a couple dozen non-tech people I've observed over the years - the most popular music player isn't Spotify, it's YouTube. And YouTube does have it all, at least for now.
I'd believe they were actually happy if there was a streaming service that actually didn't have content randomly disappear like it does on Spotify, and if customers still liked Spotify more.
To me, at least, it seems like consumers don't have many choices. They have to compromise with Spotify and others dropping content at the whims of rights holders.