I'm in my late 40s, so not that old, but I grew up with CRT TVs, of course. I always heard (note the past tense) the tube whine of every single CRT TV I watched (some were louder than others though) while it wasn't being drowned out by TV program sound, it wasn't just my one friend's TV. As for the black image on the screen, I don't know - perhaps it was plugged into a source that was paused/frozen with a black image, or perhaps that particular manufacturer had designed their TV to display a black image and no sound when there was no signal, instead of the regular white noise / "snow".
As for hearing the difference with an upgraded PSU, I made no such specific claim, so I wasn't trying to "prove" anything. Step off the soapbox on that please. I only posited a theory on a specific case where a PSU might make a difference (high impedance headphones with low bass, and spontaneous, repeated high power draw).