We music purists like our CDs because...
To which I would add that there is lot more that can be added.
In the old days the Holy Grail of reproduced audio was to make a listening experience be exactly like a live performance. That is theoretically possible though generally impractical. A good multi-channel surround system or even simple stereo can come close enough if the system is good enough and set up well. A key element is that speakers create an actual sound field, something headphones can't do. With the development of reasonable compression like mp3 it became possible for anyone to carry an entire musical library on their person and listen to whatever they wanted whenever they wanted, as long as they use headphones or earbuds. Convenience defeated realism for almost everyone not a musical purist, and thus became the market standard. Dumb'ed-down audio was the clear winner.
When CDs first came out they didn't sound as good as vimyl, especially for "re-released" original tracks. That wasn't because of any weakness in the medium (like the ridiculous holes-in-the-music argument) but because vinyl has its own properties which engineers had learned to accommodate. Just as audio engineers gradually learned how to mix and master CDs to sound good, they eventually adapted to create mixes which sounded okay in phones. High bit rate mp3s can sound good like raw PCM audio, but of course they are nearly as big too. The new goal isn't the live-performance of the old days but it isn't meant to be. It's meant to be something which sounds good, real or not. (I have in fact mixed several CDs and a DVD with phones and highest-bit-rate mp3s.)
So put all this in a car. Yeesh. A car is about the worst environment you can imagine for good audio. You have two seating positions, neither of which is very far away from the various speakers. How do you generate spatial effects correctly for both, or even one? I once worked out the transfer function math to use head-shadow effects to do it. It was messy. I was not able to determine whether the solution was degenerate or physically possible, and since no one in the company was interested and it wasn't my primary job I didn't pursued it further.
Porsche's Bose system has a surround effects feature. Sharon and I found that it made speech such as ball game on the radio less intelligible. I haven't been tempted to try it on music. I don't know what it does but I can guess. Disclaimer - the company I worked for was a Bose competitor and I understood a bit of their technology, so I'd be a biased judge.
Anyway, the point is, good audio is really hard, and in practice depends on what you are willing to call good enough.