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


Cost ? Heat? Reliability?
inna
Dan D’Agostino's son Bret certainly agreed with your premise & his co. Bully Sound still has their site up even after his demise so presumably they're some kind of going concern >
https://bscaudio.com/Pages/aboutHistory.php


Inna, some people can hear better than others in regard to Class A.

In regard to SS versus tubes, some people are music lovers, and some people are equipment lovers.

When I had an audiophile music loving friend, we swore by our "0 distortion" SS gear. I requested a CJ preamp to audition at my home, and invited my friend over for his evaluation.

The CJ was a loaner and produced apparent distortion, but even through this distortion, we both agreed that the music sounded better. Neither one of us has ever considered SS preamps, since.


However, an SS power amp simply reproduces the signal of the preamp; consequently, a high quality SS power amp is acceptable.
While I don't feel strongly enough about class A vs AB to become a television evangelist so I could spend a few billion to hire the Islamic State tosteal for me a Tzar Bomba to use against people using AB amps, I make my own class A tube amps because they are simpler to build and you can for a few hundred dollars buy parts as good or better that what you get if you spend five figures on a high end tube amp. I like my Magnepan speakers so I solve the sensitivity issue by using radio station transmitter tubes. If I use 45s by themselves I have to use sensitive speakers.But I have heard some fine sounding AB amps too.
"Why would women want audiophiles when there are better men ?"

Because we are better listeners

You're Welcome
... as already noted, because it does not always sound better. I can easily design a horrendous class-A amplifier.  Design is everything. All the practical benefits are noted as well, but i can further assure you that the cost (transformer, devices, heat sinks, etc.) of a pure class-A amp consumes resources that could be better spent on sound quality elsewhere.