It is not false for sure, but this hide the essential...
The greatest bottleneck is our own room acoustic and more than that our own untrained hearing with acoustical experiments... The main bottleneck is our brain...
An acoustic concept is not an abstraction, it is a reality that must be concretely listened to...
A system or several pieces of gear exist in a room for the ears, and the bottleneck of the system must be manifested IN the room where it is well or not well embedded to the ears and for the ears ... To understand the true specific nature of this gear bottleneck we must understand acoustic first... If not, we are embarked in a carousel of upgrades most of the time meaningless.because we are unable to listen to this gear at this optimal working peak anyway... It take a room adapted to the gear and under control for that....
Every system has a bottleneck, ie the thing that limits performance. It’s just a question of how much it matters.