I see where you're question comes from, but some of the ones you specifically mentioned I have a second opinion. I always thought Aura and Tutu were very good quality. Remastered versions of Aura and Tutu have been issued, and in both cases the remastered betters the first generation CD. Agree that Aura, Tutu, and particularly Amandla, the recording tends to be on the crisper side of the spectrum, and my experience with these is that as my system has improved these tend to sound more "right." If you heard the vinyl pressing of You're Under Arrest on a good system it would blow you away with its punchiness. I have the vinyl but not the CD for You're Under Arrest so I can't compare the two. However, I have the CD but not the vinyl for Decoy and I agree the CD quality is terrible. Based on what I hear on vinyl with You're Under Arrest, I suspect that perhaps the vinyl for Decoy may be a better representation of the recording than the CD. Long story short - to me the CD quality of these albums is more suspect than the recordings themselves. An album like Amandla, Miles' muted trumpet will get butchered if all is not in order with the system. But on a well sorted system, Amandla sounds right. Star People - sonic mess!
Why Miles Davis late alboms are not well recorded?
I wonder what Miles David would answer. I suggest sound quality was important for him (in 70s he owned Acoustic Research AR 5 speakers, one of the most naturally sounded ones then). I enjoy the quality of his early 60s and even some late 50s recording, which, to me, are recorded better than late 60s, 70s and the following dates. An exception is his (live) recording with Quincy Jones live at Montreux 1993 - a good sound quality but not so interesting content. His 80s albums sound sharp and electric, indeed pity (surprisingly1981 Man with the Horn sounds better (except Mike Sterns solo on the first track is really badly recorded) than the later 84 Decoy (the worst recorded one perhaps) and 86 Tutu (at that time, already good digital recordings were made), and 1989 Aura is digitally recorded, and again, with a poor quality). I don't think that late 60s and early 70s fusion style could somehow impose worse recording quality.
A somewhat similar picture is I think with John Scofied albums - from late 90s his albums do no sound well (except perhaps a few latest ones).
Similarly in some rock groups. For instance, the first ELPs albums (Tarcus and Triligy) I think are better recorded than later ones (why a following Brian Salad Surgery sounds worse?), Led Zeppelin 1-4 for me sound better than the following ones.
There is so much discussion about relatively minor equipment aspects that affect sound quality. To me, having a
descent sound system, the major trouble comes from how recordings are made.