IMO, Price is a tricky thing in audio. Some gear has a very limited market near as I can tell.
I know many, many people who don't even own a receiver (they have boom boxes, or iPods, or computer speakers maybe, but no receiver.)
I have no idea, but maybe less than one in ten americans owns a receiver, AV, or otherwise. Does not seem far off when thinking of people I know (and not being a jerk, but I tend to know more middle class people than lower class - not a knock against anyone.)
Out of all my friends I only know a few who own amps meant for home audio (a few may own guitar amps.)
I have to speculate the home amp market is small. And diluted. There are many companies making home amps.
That drives the price up, obviously. Some pricing in amplifiers is due to the limited market. Some is due to expensive amp designs, and some may be padding (after all, if you are going to charge $10,000 for an amp, why not charge $15,000, as your customers are probably wealthy - just a guess on my part
Now I assume Emotiva figured out some way to make money selling affordable amps (this does not mean low quality.) Internet direct helps I would guess. Perhaps limited advertising. Finding a place that could make them cheaply. Etc. If done right, I would guess the idea was that a lower price could generate more sales. All guesswork. But basic business reasoning I believe.
Sure, there are better performing amps. Noise for example. I am sure there are quiter amps. And there are certainly amps using better parts. The tough question is sound. And you can read about all the amp sound debates. But no one has ever proven to me that a conventional class AB amp, compentently made will sound much different than another competently made class AB amp, providing neither is overdriven.
And obviously you pay more for more power to some extent - but you rapidly hit the law of diminishing returns in my book. If you have 200 watts / channel, doubling that to 400 watts / channel is a 3 dB change in SPL - which is small (you can hear this for yourself, by adjusting your receiver's volume by 3 dB)