what's the point?

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.
There is no point in buying an expensive amp or an expensive anything for that matter. Buy what you can afford and components that take you to the experience you are looking for. Be reassured that amps etc. do make differences and nothing sounds the same. I have a good friend that debates this with me endlessly until we finally took the speakers out of his system and inserted them into mine. Of course my room is different, components etc. and so we tried our very slack A/B in the near field in both systems. Less than a minute, he couldn't believe it. Next my amp went to his system. Couple of minutes later he is trying to buy it from me. Not really a revelation. I do find the diminishing returns part of this interesting though. Of course how fat your wallet is the biggest factor but for me things start getting weird at about 10 k for amplification. I tend to look at the whole system and component synergy. This is where a crown amp suddenly for some inexplicable reason may work as strengths and weaknesses gel in your system. 

It's all for "fun factory" really. In the past year I've switched between a $1,500 Primare Class-D integrated, a Kenwood solid state integrated from the 70's, a $300 Kenwood power amp producing 150 wpc from the 80's, and a pair of $1,750 Cary Audio tube monoblocks. The difference between *all* of them has been extremely subtle. The tube monoblocks are definitely more different than the solid state stuff; kinda feels like I tweaked my EQ a bit. But the solid state differences were all very subtle "tip of the tong" sort of things. Not differences I would prioritize in any other hobby.

Get something that has enough power to drive your speakers to the highest listening levels you will achieve in your listening room. Get something that looks good, and is built to a quality level that makes you happy. And don't worry about how much it cost.
I would say that a lot of equipment out there doesn't really break new ground and therefore offers subtle differences and so a Crown amp may sound similar to an older Bryston. Finding those special pieces is where the journey lays for me. Rarely does price guarantee anything sonically in this hobby but the journey can get expensive and so worry about the money.  
I think technically all amps are supposed to sound the same below clipping, but they don't. And is probably due to coloration or so due to the designer wanting his sound signature a certain way. Just my opinion.