Originally Posted by Steamer

But do you understand that the bike has drag too and contributes to the overall drag figure?

If bike B has lower drag than bike A, and both bikes position the rider identically, then bike B is faster, no?

I don't think anyone is credibly disputing that the rider's body drag is dominant, and that it's a function of its size, position, orientation, and surface characteristics (e.g. clothing not flapping or billowing matters a lot).