Why would anyone want class AB amp when class A always sounds better ?

Cost ? Heat? Reliability?
I had a lot (or heard -) of class AB amps (high-end): Luxman, Esoteric, Hegel, Audio Analoque, Jeff Rowland, Accuphase, Mark Levinson, d’Agostino,...not of them all ,sounds better than Ear Yoshino 509 monoblocks or Wavac MD 805m. : the purity, detail, 3D. If you really enjoy your music, this is the best. You can’t put it very loud,  but you have to to really enjoy it. Tubes get warm and have to be replaced after a while,but a real music lover will take that in. In transistor, I had a few class A amps:some of them sounds to “dark”, detailfull,rather “flat”.
Class A does NOT sound better (as the thread starter claimed).

He doesn’t mean different manufacturer amps.
The same amp/s will sound better without any xover distortion, and the way to get it is with more Class-A bias if all else can take the extra juice that it needs to do take that extra class-A bias, and it will sound better for it.

Just have a listen to the Halo JC1 monoblocks they have a switch on the back that raises the Class-A bias quite considerably, you clearly hear which sound better, same with the Gryphon Antillion with it's switchable bias.  
Cheers George
It’s satisfying to see there is still some original member’s left here on audiogon with substantial exsperince, that said, I wanted to thank georgehifi, and bigkidz that know the truth about class A bias amplifier’s. Of all people, me and inna know about over blown publicly about an audio product, we both had a Luxman L-509X integrated amplifier at the same time, we both burned in the amplifier, turned out the amplifier had exaggerated treble that did not sound like the real event that is on stage, the bass was weak and not fulfilling, the mid-range was terrible, the sound stage was subpar at best, needless to say we both sold the amplifier’s at a big loss, 8 or 10 months old New!, I already own my main system through all this witch is pure class A system running class A digital direct to the amplifier that is class A, as bigkidz said in his post, very emotional real sounding system, this system made red neck’s cry, LOL!!!
class AB is MUCH more efficient.
class A produces an INCREDIBLE amount of heat, at idle.
Anyone has Mark Levinson ML-2 to spare ? I don't think so. Old Gryphon ? Nothing again. Very bad.