Here is an 86db/w speaker eating up 600 watts with dynamic music at not insane volumes. Room size can mean the difference between needing 100 watts and 400 watts to avoid clipping for the same speakers playing the same music at the same volume at the listening position.
That's Alan Shaw of Harbeth and the video is a surprise to me. I started my interest in power demands when sharing with Harbeth at CES shows. I was back then arguing for more power not less. It was with Harbeth at shows that I was measuring with an Oscilloscope and recording numbers. Alan Shaw argued vehemently for modest powers being sufficient. I was looking to justify the 250 watt partnering.
I never saw power such as this video is showing, and of course the one uncertainty here is the amplifier power meter, how do we know what the accuracy of those is or how they calculate actual power. Is it for example a volt/amp measurement? If so then very high power levels could be recorded by an amplifier that was rated at say 200 w into 8Ohms but which had large current reserves.