It is not true mainly because all components are built to a price point so that means the best parts are not always used - think how many manufacturers use V-Caps or Audio Note non-magnetic resistors, and how many components are build with copper chassis or point-to-point wiring.
True or False?
Many high-end manufactures deny the benefits of tweaking their components with upgraded power cables, fuses, etc. We all can agree that even the best speakers respond to room placement but is it true or not true in (your experiences) that the better your audio components are, the less they respond to various tweaks?