So how can a great system solve less than great recordings

Why do you imagine a great system can make a poor recording better??

A great system reproduces accurately what is in the groove/pits, that's all.

If you want to go that way, get some new-fangled digital enhancer that makes the recording sound more like what you want to dial in.
And kills the soul of the music.

"Some of my best recordings are from the 50’s, 60’s, and 70’s. They knew how to record and master back then, today it is mostly a lost art and most remasters suck in my opinion."

How right you are Audioguy85!!

Me too, give me an original Decca or EMI pressing every time.

Today's problem is digital offers producers and engineers the opportunity to tinker.  They just can't resist it.  So in most cases everything that was good about the original recording is corrupted 'we need a bit of heightened this or toned down that'.

This applies equally to today's new recordings in which the digital desk is ever present under the hand of the engineer who loves to fiddle, thinking that such tech wisdom as he may have knows better than the musicians who created the performance.

JUST LEAVE IT ALONE.

A live performance (at least of acoustic instruments) doesn't contain any engineer corruption.  So, if you want to reproduce it accurately, dump the engineer, or at least tie his hands.