Can a great system make a mediocre recording sound good?

A lot of complexity in this question. In my mind there are 2 fundamental different ways to listening to music on a reproduction system: 1) you can listening to the musical idears ("Hey listen to that baseline. Listen how she waits a quarter note before she ends on the G") an 2) you a listening to The Illusion of the performance ("Now listening carefully how the the instrument behind the guitar moved back a little and suddenly separate! You hear it's a clarinet?")

Both ways of listening will improve when you upgrade, but only the latter is critical.

A rising tide lifts all boats.  A better system makes it sound better, but doesn't give the illusion of a well mastered recording.  And if played right after a well mastered one, the difference can be striking until your ear adjusts. 

Agree that the system should be geared to get the best out of music, and not to serve as a demo for audiophile recordings. 

You have a very nice system. You probably listen to many recordings and are totally satisfied. If you listen to garbage it is garbage and not your system, plain and simple. Enjoy your system and the music..

Started tape trading in u.s. u.k. Germany, Sweden,

been sent 3,4,5,6 gen demo and live shows.

most sound horrible, but that’s part of the fun of it. 
 

cassettes get play on my,Panasonic ex-c45, and the National.

a great sounding lil beast!

A great system makes a mediacore recording sound more mediacore.