Could be that many of their speakers have been and are over rated. Sam Tellig and John Atkinson of Stereophile seem to be in love with the company's product. The other reason is that the Harbeth sound appeals to a certain audience, and listener.
Sam Tellig would not be caught dead playing rock music or even jazz. he was strictly, and officially a classical music lover and elitist snob, and also automatically anoint the speaker with special status.
There is a continuing assumption in audio that great speakers "should" sound good on any type of music. I am not sure that is totally true in reality, though it is a noble and worthy goal to pursue if you are building these things.
I have to somewhat agree with the member about "Harbeths on sale". Interestingly, there was for a while a run on KEF LS-50 placed on the selling block. Maybe, reviewers over enthused about them. Or, maybe they are too analytical, and also don't have much bass. Nevertheless, I counted one day last month, approx. eight LS-50's on sale on audiogon.
What bothers me about companies like Harbeth is how they can justify retailing a speaker like the 30.1 for $12,000 plus. However, in the over enthused and less critical reviews world of hi-end audio, price too often predetermines the expectation of great value and high end performance.