My response was--if they were so good, why do so few companies offer them?
Still very much around, but primarily in the high end model turntables. Good examples include Walker, Kuzma Airline, Rockport, Air Tangent, Clear Audio, and Eminent Technology.
Any analog gurus out there who could clarify the reason they fell out of favor.
They didn't fall out of favor, just a lot more expensive to build, and there are many traditional tonearms manufactured today that far exceed your friends B&O.