I was told that most remasters are unnecessary and are only done to either extend the copyright or as a marketing gimmick to resell the music. Do you find that to be the case?
Just from a music listener’s POV, I find most remastered songs disappointing. I first thought the sound would be better, but usually it’s just different, not improved. But that’s just my unschooled-in-sound-engineering opinion.
Absolutely not!
Generally speaking, remastering is done to produce a product with better sound quality via better, more advanced electronics.
For example, the early 16-bit CDs were remastered using early digital filters of poor quality vs what is now available.
Remasters can also introduce a product to a new audience - i.e. vinyl for those who have never experienced that format.
Also, High Resolution music files using 24-bit technology gets MUCH closer to the master tape than 16-bit/44Khz CDs.
The Beatles catalog was remastered in 2009 to 24-bit High-Rez downloads...and sound light years better than the original CDs issued.
A few years ago, Sony re-mixed/re-mastered Miles Davis’ iconic jazz album “Kind of Blue” to 24-bit HiRez file and corrected a speed problem in the original 2-channel mix.
In recent years, a few of their albums were re-mixed from the original session tapes then remastered to 24-bit/96Khz files using current state-of-the-art digital products and the sound quality is arguable the best...and I have UK 1st LP pressings of their catalogue and two “Blue Box” sets.
Finally, different engineers can produce different results in terms of sound quality. There are “Golden Ear” engineers and “Tin Eared” engineers - each producing much different end products. Crap sound vs “Real, lifelike” sound.
Sadly, many of the “young” engineers are pushing compression in their remastering projects.
So to answer your question...
Remastering, generally, can provide higher sound quality if done correctly and re-introduce an artist’s products to a new market.
It depends. A lot of the remastering is done to renew copyright because it actually does expire in England. That being said if the engineer is good the remastering can be good. Steve Wilson, who’s become the prog rock remaster king, makes AMAZING mixes. He insists on getting all the tapes, false starts, rehearsals, thrown out songs, everything. Not necessarily to use them but to get a feel for what the band was trying to accomplish. Then digitizes then base tracks and remixes from scratch. His mixes are renown for being very crisp, very clean, and having plenty of room to breath.