An improbable and ridiculous scenario, yes? And yet, it is perfectly normal to encounter the same mentality when it comes to cycling. One question I get asked that absolutely puzzles me, is whether I am "moving away from upright bikes" now that I am comfortable riding a bike with drop bars. What?... Are people who take up running moving away from walking? Similarly, I am amused when someone congratulates me on becoming a "real cyclist," now that I can ride a roadbike. I suppose that means runners are the real pedestrians?
Just like there are many forms of pedestrianism, so are there many forms of cycling - each serving its own purpose. The distinction between city bikes, roadbikes and mountain bikes is not so different from the distinction between walking, running and hiking. Walking is not a sport, but a casual form of pedestrianism, a natural and low-maintenance way to travel from point A to point B. It is done in one's everyday clothing, while comfortably carrying items on one's person. Taking up running or hiking is all well and good, but you'll probably still want to walk to the grocery store.
My upright step-through bicycles are my two-wheeled "walking." They are essential to me, no matter what kind of other bikes I ride for fun or exercise. I am more comfortable than ever now on a roadbike, but when it comes to going to work or running errands - or pretty much any kind of transportation - I will always revert to the upright bicycle with a step-through frame, fenders and racks. As with walking vs jogging, there is no conflict between these two forms of cycling as far as I am concerned. They co-exist, each in their appropriate context.