I can see why they guard the form of the bikes used. Competitive team road cycling is, amongst other things, about the tactics of multiple riders using shared

I can see why they guard the form of the bikes used. Competitive team road cycling is, amongst other things, about the tactics of multiple riders using shared aerodynamic advantage. If you make everyone more aero by say using recumbent bikes you diminish the advantage of teamwork. You’d lose all the inter-team horse trading that goes on between rivals in breakaways or mountain stages. No more tight sprint train finishes. There’d be no surprise attacks because there’d be no way to conserve energy hiding behind a rival waiting for the right moment. Everything would be full gas all the time and could mostly be settled by looking at pure power numbers. You’d still get a race but every stage would be a simple time trial. Effectively road racing would become a very different discipline. Like giving all the riders ebikes. It’s still a form of racing but you lose a big part of what makes a team stage racing compelling. I’ve always wondered though why they couldn’t allow open vehicle stages for some time trials where the riders are on their own anyway. I think that would preserve team cycling and still be fun.