Unless you're talking about a totally different kind of cycling design which we would not recognize as a bicycle, probably not much. The racing bikes of today are really only marginally "better" than similar bikes of 50 or more years ago. This is assuming that by "better", you mean faster (and they aren't really faster anyway). But of course, there are different ways of defining better. This whole topic is really only of interest to people for whom technology is the main thing, and the bike is a commodity of technology. The more you value technology, the more you become dependent on it. There is a whole other class of people for whom bicycling is about simplicity, minimalism and self-reliance, and also anti-mercantilism to some extent.

You can always make a formula racing car faster by turning into a virtual low-flying airplane, but then, is it still an automobile? Do you want bicycling to be a contest of technology, or one between people? I can just imagine how some of those on the technology side of cycling probably also drive street racers with those blue lights shining out from under the undercarriage.

How much better do we need, exactly? My retro-grouch lugged steel framed-bike with the cheap low-TPI kevlar-belted tires on it already goes faster than I can reasonably ride safely most places that I ride.