Why have capacitors improved so much over the years?

@troidelover1499

It is still just salt

not sure you'd have a lot of chefs and gourmets in agreement... 

@jond - NOS capacitors, huh? Uh oh, another crazy rabbit hole! 

@cakyol so you think it's all hype? 

Specifically, though… Any amp builders or speaker builders to describe the tech?

@noromance, thanks. 

@terry9 thanks for your thoughtful replies. Can you give an example of great air dielectric capacitor?
@puffball08 - I used that database to pick new caps for one of my amps, very informative.  Quite an undertaking…

Obviously, better manufacturing in general will lift all boats, but clearly the audiophile niche is highly active and innovative to some degree beyond mere marketing.  The premium audiophiles will pay has to explain the R&D that goes into VCaps or Mundorf or Duelund or whatever, and there must be legit technical advances happening, whether proprietary or otherwise.

@ieales - thanks for the link, cool history.

@terry9 thats a wild website… I have no idea what I’m even looking at with those air caps!

@millercarbon - that link has been posted in this thread already.  The original question was actually “why” though…