RE Thriller
Given the time frame of it's release and the popularity of it's artist then, recording quality could have been way off the mark and pretty poor actually, and album sales would still have sky rocketed.
I don't recall hearing one person then say, "I bought the record or disc because of the quality of the production."
Just like Elvis and the Beatles before MJ, record sales simply weren't based on the quality of the sound... but merely the 'sound' or style if you will, of the recording artist.
Still today I'll buy the stuff I like the sound of on the radio or that I've heard online in a disc, only to find out it is lacking when played back on my main system. So it gets played less or played on a lesser system.
the motivation for the purchase remains the same... by and large I've deemed it popular enough or found it appealing enough to purchase. Seldom if ever am I able to preview a prospective disc on my main rig.
Quality quite often is merely an afterthought or anomoly in pop & rock. The overwhelming majority of that audience simply wants loud... not quality. 95% of the time, when at those folks homes they'll show off their new CD by turning on & up the system just that fast... to paint peeling levels and then say, "How do you like that? Sounds great doesn't it?" .
Normally it doesn't. When they come to my home the first time, everyone of them will say turn it up even if I'm already in the low to mid 90 dbs. I'll tell 'em I can't, it trips the breakers.
I'm pretty sure now, most of my pop and rock oriented friends are almost deaf. In fact some very nearly are.