1. I believe NPass is speaking to a perfect electronic interface world, which would necessitate building ones system around a PP, as opposed to trying to insert one into a active preamp system
I believe it does, and that "perfect electronic interface" is available in systems much much more than not.
1: If the source has more output voltage than the amp has input sensitivity to give full output. This is maybe in 100% of cases.
(I have yet to see a source with less output voltage than the amp needs input voltage to make it clip)
2: The ratio of output impedance to input impedance, of the source to passive and from the passive to the amps, are both 1:10 ratio or more, this also would be in at least 90% of cases.
Then you have what you call, that "perfect electronic interface" for a passive to work as it should, which is getting the source signal to the amps in the most transparent, undistorted, uncoloured, unhindered way.
Cheers George