Bullshit on top of nonsense with a healthy dose of idiocy.

Sources, DACs and amps are solved problems as long as you buy stuff made by engineers who use measurements for validating their designs and not by audiophiles with golden ears.

Headphones and speakers are more problematic, especially since there are the headphone + head or speakers + room interaction. Optimizing this interaction makes sense. However, that's not with audiophile tweaks but EQ and, for speakers, room treatment (e.g. absorbers).