Law Of Diminishing Returns?

"is a wagyu ribeye 4x better than a choice ribeye"?

Yes.

Audio equipment?...To me...not so much after you reach a certain level...

Don’t ever buy a new car, its value drops 30% the second you drive it off the lot! Same thing with hifi, but if you want new and exciting with a full warranty, you’ll buy new. 

Certainly buy runout gear, examples Focal Clear phones $2200, bought for $800, Audio Physic Speakers $5700 bought for $2900, Cayin tube amp $3600 bought for $1900 there are plenty out there. I rarely pay more than 60% for anything. 

For someone who's never had anything but a clock radio or boom box, an Acoustimass 5 system would probably sound sublime. For someone who is well off, a $30,000 amp may be the starting point. In other words, there is no magic dollar level where the sound improves in a largely noticeable manner. 

Over the years, I have replaced gear with more expensive gear a number of times and have always gotten a rewarding improvement in sound quality.  I always keep the gear being replaced until I'm sure the new gear is a worthwhile upgrade. I'd bet I could keep on doing this all the way into top of the line gear. 

We really shouldn't worry about what other people are spending.  You buy what you want and let others buy what they want.  It works out well that way.