Interesting reasoning in this thread.

Just a few thoughts on the original question: There are two differences between full-length housing and housing stops. One difference is the extra length. That section is straight, not bent. So I can't see how it would create much friction as long as the cable wasn't rusty inside and was clean when inserted. The second difference is the cable ends in the stops. In my experience a poorly-fitted cable end can produce a fair amount of friction, more than 20 extra inches of housing. On the other hand, if I were building thousands of bikes a year I could save housing by installing stops. To me this argues for stops on high-production, lower-cost bikes.