In cycling one key is drafting. We have a few guys where I live that do well in big national races. When they show up on the Saturday group ride, weaker riders can keep up thanks to the advantage of drafting. A rider has to be about 30% stronger than me to pull away when I am drafting him.
And surviving three weeks of racing, often over very difficult terrain.
Your "average" pro cyclist (the domestiques) dope because that's the only way get through a grand tour. It's not about going faster, it's about survival.