But, a major motivation to remaster old records is due to copyright expiring on the old recordings, particularly in Europe. A remastered release is considered a new release in terms of copyright, which can therefore be protected, I believe.

The depressing mountain of very cheap public domain John Coltrane (for just one example) "reissues" by every man and his dog was foreseen by the record companies.

And, while I'm here, these cheap reissues of expired copyright recordings often say they are "remastered" when all they've done is tweak the equaliser and added some phasing. For no other reason, these RVG remasters are great in order to identify the reference recording amongst the deluge of bedroom re-hashes.

(And, RIP Bobby Hutcherson. RVG's remasters of his recordings sparkle).