>>2041898They didn't have teflon-lined cable housings and cables we have now, slick enough to run in one piece all the way from shifter to rear derailleur and still shift shit, so they had to minimize housing usage to just the derailleur itself where it's almost unavoidable. Bare cable goes out of downtube shifters, runs parallel to the downtube (duh), gets turned around via sliders, rollers or a very short run of housing, then runs bare parallel to the chainstay and enters the scratchy tube of doom to the derailleur.
