What happened to Linear Tracking Turntables


After a lengthy discussion with a fellow audiophile who owns a B&O 4004 linear tracking turntable, he wondered what ever happened to the genre. According to him, they do less harm to the groove walls than do current arm geometries. He claims that records he has played hundreds of times sound basically the same as new with minimal wear. My response was--if they were so good, why do so few companies offer them? I'm sure there is a valid reason, but neither one of us is knowledgeable enough in the area to argue the point. Any analog gurus out there who could clarify the reason they fell out of favor.
jig
Was the Bo linear arm a really good idea, I once had one and my dad has one but doesnt that needle sorta "slop" around in the groove trying to find its path? And does that cause damage to recordings that other arms might not, just curious here and it is a un-educated guess.
There is another thread started in the last few days over on the Vinyl Asylum and the variety of linear tracking TTs in use over there is pretty astounding... As I write this, I am listening to a Yamaha PX-1, which sounds great to my relatively untrained-in-top-vinyl-rig ears. Oops... that's the problem with 45s... they're done pretty quick...
Not all air-bearing linear trackers are very complex. The Conductor arm by the Cartridgeman, is an example of an air-bearing with a low pressure pump, thus getting around the problems of high pressure systems.