It’s a tiny percentage of the population that even knows what a FLAC file is
Me!
I’ve got thousands of tracks on a USB SSD
I haven't bought a track (as in "ever"). I have all my CDs ripped onto the music server at home. Most recent CD purchase is "decades ago" so they are all getting really old now ... the Xmas play list is still valid, once a year.
I have quite a long list of favourite artists in Spotify (in the car). I have a Spotify subscription (home) but have never bothered to set up the car to use that. At home we use Sonos if we want music (which isn't all that often). Can't remember when I last played my ripped CD tracks, other than Xmas Playlist. We just play something off Spotify. Or we ask Alexa to play something - not bothered to figure out how to get Alexa to ask Sonos to do that ... I tried it in the early days and the interface was so useless that I gave up, and haven't been tempted back again.
When kids are in the car they bluetooth a Playlist from their phones ... no idea why they want to listen to specific tracks, maybe I did that when I was their age ... wife and I occasionally do bluetooth for Podcasts. Wife and I probably listen to Radio more often than we use Spotify
I've read several reports here of the better audio quality of Tidal. So although I stored that in the back of my mind I've never attempted to try that in the car ...
I've worked in technology, specifically software, all my life. Generally I hate all IT as incompletely built and an arseache to use. Only thing I can think of that was the exception was when I first got Sonos. I read a review from a software guru I respected (other than that one piece he only ever wrote articles about software ...) where he said that Sonos was the only IT thing he had plugged in and it just worked. On the strength of that I imported some gear from USA (tells you how long ago that was, as it wasn't available for purchase here ... still got it; still working just fine.). Hugely expensive at that time / via that route. And, yup, it just worked. That was long before they brought out Phone APP and monkeyed with the UI to make it opaque - marketing folk got the better of the use-ability department I expect