They didn't have a choice. Do you know any who race on them now there is a choice?
Well, probably not. But then did they ever ride the same bike for ten years. Or do their own maintenance, or leave their bikes parked outside work in all weather ? Of course not. the comparison is absurd.
I have needed to replace bearings in headsets, maybe I'm a freak. Except of course if you google headset bearings you'll find them stocked everywhere (At least for the common sizes) they can't all be stocking them just for me.
I can't be arsed to argue about something so trivial, I though the advantages had been accepted by everyone. And the continued availability of quills was due only to the aesthetic appeal to some. I'll leave the last word to Sheldon, writing over a decade ago;
While traditionalists may bemoan the
change, it appears that the move to threadless
headsets is inexorable, since they offer
so many advantages to the manufacturer —
and even a few to the rider.
Source - http://www.adventurecycling.org/resources/headsets.pdf
