Possible reasons: your vinyl LPs have much better recordings (lots of CDs are mastered poorly, especially ones from the early 80s), your 80's hi-fi set is better than whatever you use to play digital music, your digital music is poorly encoded. Or, more likely it isn't better and you just think it is. Ever do a blind test to find out?
CDs go down to 20 Hz which can barely be heard anyway. Also, this is going to sound really pompous, but don't listen to recording artists when it comes to actual theory about the stuff they use. They may get great results but a lot of them buy into ridiculous bull**** like expensive cables and other nonsense. Talk to an electrical engineer if you really wanna know how stuff works. Talk to the people that actually design and build the systems the artists use.
A good way to rule out someone's understanding of audio equipment is to ask them about double blind testing. Audiophile idiots insist double blind testing is somehow inherently flawed, and they use this as a rationalization for why double blind tests show time and again that the bull**** they buy is complete snakeoil.
Bassoon, n. A brazen instrument into which a fool blows out his brains.