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

It’s not true it’s not that cut and dry many very high quality amps may have the 1st watts say 20:watts in pure class A 
then switches to class AB.  That being said , inside the Quality of the parts have much more to do with the final result of the sound .
I owned a Audio store until 09 and Had many parts modded or  upgraded,for the vast majority of mfgs use average parts at best .
on average 25% or less of the cost actually goes into the electronics,the rest over head and markup. That's how 
Modwright was able to be so successful by putting in Premium 
parts in the most critical areas. Companies like Gryphon for example use top of the line puts throughout ,and are exceptional 
in sound quality.  That being said ,not everything is in               black and white. As well as the engineering  and their design .

We talk, but are we communicating; some people have equipment to hear music, while others have music to hear equipment. Which camp do you fall in?

If one is an obsessive music lover SS preamps never sound quite right, however, obsessive equipment lovers claim tubes give distortion.

I think tubes versus SS is more profound than Class A, AB.   Personally, I would not want SS preamp no matter what class or how expensive,  SS power amps are OK when necessary.  Could not stand ARC preamps that were SS, I don't know if they still make any SS preamps?

While theoretically class A is better, given same quality of parts and craftsmanship, I'm sure there are few people who could pass a blindfold test to distinguish which was which.

some Class AB amps sound better

I say it again.
If they can take it without strain on anything, those same A/B amps will sound even better again if their Class-A bias was turned up full, as you eliminate any xover distortion, as it never goes into Class-B which gives xover distortion no matter how well designed

Cheers George

Why would anyone prefer anything besides Audio Research monoblock tube amps, when they are so awesome?  For only $70,000, plus a 5 ton A/C unit to cool it, you could begin building a truly great system.  All you need, besides the above, is a $10,000-20,000 preamp, a stupidly expensive source or three, and a room to put it in.  Then, you could chase away all of your friends by showing them the intracacies of minute passages of music that really show it off.  I prefer the Class A Audire Monarch towers, and a Diffet 5,  but settle for a trio of Audire Fortes (Plus two Audire Diffet 3 preamps), and really love my music, even when listening to Jazz 67 on XM, despite its inferior sound.  Why would anyone prefer a beautiful Ferrari to a Bugatti, when the latter is faster?  Why would anyone prefer a wife of fifty years, when a Russian model is cuter?