In today's context I guess I can understand that, but back in the day, especially on a bike that was ridden well away from town centers I can see plenty of advantages to having a re-buildable valve. Even today on an unsupported tour I'd love to be able to repair a presta in the middle of nowhere if there screw part were to release and shoot of of the valve rendering the tube useless. Sure, I can bring another tube, but if the first one could be repaired, why not?

I'm guessing you don't patch your tubes either eh?