ATC, Bryston, Manley and EAR make amplifiers suitable for professional and audiophile applications. Also didn't Boulder start out making pro-oriented amps.
I agree with the tone of Shadorne's comments about audiophiles wanting a softer presentation than what is useful in a studio environment.
As an aside, there is a school of thought that takes the position that power amplifiers, while important, just aren't that critical to getting high quality sound. Peter Walker of Quad and Siegfried Linkwitz are prime members of that school. Historically, at least for solid state designs, amps didn't become important until Apogee came out with their sub-2 ohm speaker designs. It was then that you saw an explosion of pricey, high current designs and people started to talk about how amps sounded.