People don't because they can't, other than to present bike touring as a comparative contest and then it falls apart because it isn't.
Saying it challenges your traditional definition in an evolving pastime is like trying to describe a river with a snapshot and trying to stop that evolution by putting a stick in the stream. Bike packers challenge the definition of panniers and ride. Ultralight tourers challenge the definition of loaded and survive. Endurance racers challenge the definition of distance and arrive. E assist challenges the definition of input power. Big todo about little. Next week we will argue the challenge that trekking bars make to North American handlebar perceptions... what, no drops!