>>1561192The idea of using different wheel sizes dates back to the late 1800s. The 700c/24" design that Bill Boston came up with and Terry adopted was specifically so that smaller riders could have a short horizontal top tube without suffering from severe toe overlap problems. The industry dropped it in the late 80s because bike shops didn't want to stock 24" wheels, tires, and tubes. Also, the aesthetics were off-putting to some, the bikes got a rep for having twitchy handling, and it made manufacturing that much more complicated and thus more expensive. So they dropped the design for 650c, which was then replaced by sloping top tube 700c. Sloping top tube, incidentally, was introduced by Giant mainly to shave manufacturing costs, too. Uses less material and allows for fewer sizes.
You seem to think that the UCI is some all-powerful malevolent organization, but they're really not that relevant, because the great majority of bikes sold have little to nothing to do with UCI-regulated events. When you're wondering why the industry doesn't do this or that, it almost always boils down to manufacturing, marketing, and retail. It's why the MTB industry wants to kill 27.5 and get everyone on 29. The UCI doesn't give a damn, but it reduces COGS for the big manufacturers. And if they want to push something in road bikes, they will make the UCI accept it, as they did with disc brakes on road bikes, and they're continuing to do with aero. Or they'll just invent a whole new category and push that, instead, as they did with tri and gravel.
