Looking For 90% of the performane of the super expensive cables for much less money

Those last few percentage points are everything, it’s the whole enchilada.

It’s open ended to some degree, an 'impossible to reach' perfection... so each person has to decide themselves where and how, exactly... to try and bite down on infinity...

“It’s filled with stars.” 

I strongly disagree concerning the few percentage points.  My main system sounds 50% as good as a $1.4 million SOTA system.  However, it is already as good as nearly all the systems I've heard in stores, friends homes and audio shows.  Maybe 90% as good.  My system is the whole enchilada as is.  Unless one has compared it to the best, it is good enough for all those audiophiles posting on Audiogon.  The 12 Omega E-Mat tweak did it for me.  It elevated music reproduction to the highest echelons without costing an arm and a leg.  I'm not looking for perfection.  I'm looking to ameliorate annoying sonic problems and elevating the enjoyment so that I'm anxiously waiting to be enveloped with great music all day long.  

Some or many audiophiles deem the hobby as one of striving for perfection.  I feel sorry for them as that leads them to be unsatisfied most of the time.   I'm using custom built amps/pre/phono/speaker cabling/turntable/cartridge/arm which are a decade+ old.  The tweaks are the only newer items, mostly related to vibration and room acoustics.  When I sit down to listen to music, I don't think about how I can make my system more enjoyable.  I'm shocked at how wonderful the music sounds, even acoustic 78s.  

The real percentage remaining for most audiophiles, from what I can tell, is probably about 200%. If not more. Heck, there were some weeks SQ would double when I got up a full head of steam. Or maybe easier to say it that the system performance has the potential to double or triple or perhaps quadruple. It’s just people frequently don’t know where they are on the performance curve, where they should go, or how to get there.

Yes, when I said 50% as good as the best I've heard, that's about twice as good or 100% better.  As a teenager and in my 20's, I did not know how advanced my audio system could sound.  Many people are just not aware of how great an audio system can reproduce music.  In my youth, I never considered room acoustics which was a huge mistake.   Audio stores didn't talk to me about it back in the 70s and 80s. 

I'm 62 now and have had much experience, including as an amateur recording/mastering engineer.  I know how much better (or worse) a system can sound.