It makes me laugh all the clowns who think they can do a better job of mixing than the professional sound engineer the artist himself hired to do it in the first place.
> clowns who think they can do a better job of mixing
mixing and mastering are at different stages of creating the media
mastering is what happens after the mix is finished
A lot of times it’s due to technological improvements that are capable of reducing ambient noise artifacts in the source recording older technologies couldn’t reduce. Such as tape wow snd flutter. Most of the remasters I’ve heard are an improvement over the original masters. They are certainly no worse.
CC
Christopher Cross’s amazing guitar solo outro on “Ride like the Wind” is mixed waaaay down. In an interview, he intimated that was a mistake and he would have preferred his solo to be more audible but was a bit intimidated by other guitarists on the album (Larry Carlton, Jay Graydon, Eric Johnson)
Mastering, as noted above, is completely different.
One version could have dynamics compressed, top-end rolled-off, bass loudly pumped up, vocals “squeezed” or lack of space/air on the mastering.
It really gets down to the ability & the “golden ears” of the mastering engineer and the demands of the label.
As someone who has provided technical assistance and received album credits on a handful of classic & iconic albums (Rod Stewart, Doobies, Peggy Lee, Eva Cassidy, Searchers, etc), mastering is more of an art than a science.
Of course, the quality of the mixing and mastering equipment makes a HUGE difference, too.