Studio/Performance Amps for High-End Systems?


As a practicing (hobbyist) keyboard player and audiophile, I am familiar with why one would not use a guitar amplifier for a keyboard, for example. But, I notice that some of the finest brands of high-power power amplifiers for recording studios or live performances (QSC, Crest, Crown and more) cost hundred or thousands of dollars less than high-end "audiophile" power amplifiers of similar or fewer watts/channel. The specs of these musicians' amps, designed to play 20-20K full-range sound through very low impedances (often as low as 1 ohm) seem to equal those of, say, a McCormack, Classe, Krell amp.
Is there something I'm missing here? If one needs 500 wpc or more, why buy a McCormack DNA-500 for $7K when you can get a QSC with 800 wpc into 8 ohms, capable of driving a 1 ohm load, for $2500?
toxrtp
Onhwy61- And which of those companies offers a 500wpc power amp for $2500.00?(Read the original question) I know beyond doubt there are a lot of people that are happy with a "softer presentation" or a "warm, sweet, fuzzy, tubey" or whatever sound from their equipment, or that can be satisfied listening to PA gear. I'll never tell someone what makes them happy in their listening room is wrong. Like I said: Enjoy the savings.
As a fellow pianist (and keyboardist/electronicist), I'm interested in this, but from a slightly different angle: I'm interested in using home speakers in performance. The ultimate goal is a higher-quality sound that fits in acoustically with other instruments, even though the source may be a keyboard or laptop. This motivation has resulted in things like this hemispherical speaker:

http://www.electrotap.com/hemisphere/

I'm wondering if a Ohm Microwalsh, for instance, could be driven with a small instrument amplifier (Acoustic Image?).

Any thoughts?
Why? There is definitely a compromise using an instrument amp. The little things like RCA to 1/4 inch adaptors for the jacks will degrade the sound more than you think, especially balanced to RCA adaptors (different impedance).

I owned some fairly sizable clubs and have played with Crown, QSC, Crest and more. Amazingly abusable but that's it. Yes, if budget is an issue, a $300 used Crown will give a lot more volume than a $300 audio amp but at a great expense...Inexpensive studio speakers are the same way, lots of volume but harsh and lacking in the very highs & lows and definitely not smooth. Yep, you can get custom designed ones from companies such as JBL which cost a fortune but are amazing sounding.