Affordable vs. ultra expensive speakers - what's the difference?

That depends upon you and where you are in your audiophile journey.  $50,000 speakers are an endpoint you build your system around think long term investment.

3k speakers could be an endpoint if you are satisfied with the sound but will be a limiting factor in the future if start improving the supporting equipment and will probably be replaced, maybe several times with the possibility of spending much more than the $50,000 depending on where you end up.

The difference is the importance of sound /  music to you now and in the future.

I still miss the robot references.

What does 2% sound quality improvement sound like?  Is this based on 100% or 110% sound quality?

Track Days!!!!

https://www.tracknightinamerica.com/

I can't drive 55

@mahgister 

Yes I'm being a PTA but it's been bugging me so here goes.

What is your definition of acoustic?

If you are using it as a noun there's an "s" on the end.

ADJECTIVE

1. relating to sound or the sense of hearing.
   "dogs have a much greater acoustic range than humans"

2. (of popular music or musical instruments) not having electrical amplification.
   "a sad, gentle acoustic ballad" · 

NOUN

1. (acoustics)

   the properties or qualities of a room or building that determine how sound is transmitted in it.
   "Symphony Hall has perfect acoustics"

2. (acoustics)

   the branch of physics concerned with the properties of sound.
   "Tyndall lectured on acoustics"

3. a musical instrument without electrical amplification, typically a guitar.
   "these German-made acoustics are a pleasure to play"

or I'm just being an Ahole but I may not be truly understanding the philosophy your trying to convey with the term.

Got it.  I think it's just a grammar issue which could be a USA grammar issue???

psycho-acoustic"s" would be study of how we perceive sound

psycho-acoustic would be used to describe one of the qualities of perceived sound. 

I was trying to make sure that acoustic wasn't something completely different than acoustics.  In the future I'll just mentally add the "s" and we're good.