Ignorance is bliss,I'm told. But I know from personal experience, back around '96-'97 Soundstream made an amp that was designed by Krell and to their standards. I took the amp apart once to see if it was up to high standards of home audio and beleive me, it was built to a pretty darn high standard, Looked to beat out the mid-fi equiptment we have on hand today. It would run all day on a one ohm load. I ran two channels of it bridged into a 2 ohm load for almost 2 years and never had a problem or any over heating. It was one a thousand made. But still, your statement is way off.
Their were other companies that built some high quality car audio, also.
Of course $1800 for a car audio amp, or any amp is a bunch of money. But to make the statement that 12 volt amps are junk, is not a smart statement. But, if you buy from Tweeter or other appliance stores you most likely will get junk car audio equiptment.
I can't imagine 'car audio' has all gone to the dogs since I messed with it.
Btw, in the late 80's Bob Carver and one of the hi-end mags did some comparisons of amps (12v vs. 110v) with a pr. of Maggie's and the 12 volt amps didn't do too badly. Held their own in some respects. I remember back in the mid-late 90's Wes Philips had a 'car audio' column in Stereophile every 3 months . I doubt they would have given 'car audio' an editotial spot if it wasn't worth a darn or if it wwas junk.