what's the point?

https://web.archive.org/web/20190311201740/http://www.tom-morrow-land.com/tests/ampchall/index.htm
According to this, all amps that are played below clipping sound the same (indiscernible). So what benefit does it serve to purchase an expensive amplifier that may use more expensive capacitors or other parts?
Oh, and what pricepoint does the law of diminishing returns kick in for a class a/b amp/integrated rated at say 150 watts per Channel  @ 8 ohms capable of increasing power at 4 ohms and still being stable?  Thanks.