So how can a great system solve less than great recordings

I would guess you need two systems. Or atleast an EQ.
The better system you have, the worse those crap recordings will sound.

Most systems owners, even those with extremely expensive esoteric systems, have never heard completely flawless sound reproduction.  It is a fantastic jaw dropping experience, and a life changing event.  I've heard a lot of systems but let's talk about "really good" systems then, to be realistic. If you get a crappy recording, you will hear all its defect BETTER.  It might be more objectionable.  You might never listen to an mp3 again.  When you put on a good recording, you will always hear some defect.  Nothing is perfect.  It depends on the resolution of your system.  You will enjoy it more.  So in conclusion, you will throw out more junk and appreciate the good stuff and enjoy it more. 90% of my record collection was junk. Which is more important, systems or media?  Neither. 

Dont think an EQ stands a chance to improve recording quality.  

jumia

Of course not. . . 

.  . . but an EQ might make enough of a difference to move something from the "unlistenable" to the "listenable" category. 

Should this matter to you?

If there's music you really love that's only available in a format with relatively poor SQ, it might. 

I've found the under $200 Schiit Loki useful in this regard. 

@stuartk ,

Agreed. On a couple of occasions I have put tracks through the open source Audacity software to add a little treble to those which seem to desperately be lacking treble.

It’s a bit of a long-winded process of trial and error to see where the sweet spot in adjustment lies - add too much and you start to lose even more resolution elsewhere.

Sometimes, on certain albums, it’s just bewildering how they came to make such appalling mastering choices in the studio.

You wouldn’t want to remaster your entire collection, but once in a while it could be worth the effort to DIY.