Number 1 and 2 are the most important. Hard to come up with a % factor
You left off the quality of the recording that would be next.
After that, it is not much of an issue in modern, well designed components.
But, of course, you cannot match a low powered speaker with a low impedance speaker with low sensitivity and a need for volume


But, that is not the fault of the component, just the selection process.
Hearing was mentioned above, but that is kind of fixed, not changeable, got to live with it.