I have a friend who’s into cycling in a big way. His bikes are his form of transport, and he also does serious mountain biking. He thinks nothing of spending £1000 on wheels or (disc!) brakes or gears. You can easily pick his road bike up with one hand because it weighs so little. As opposed to the mountain bike which weighs a ton, some of these bike frames are weighed in grams. It’s all to do with the design and the materials. They’re ultra light, ultra strong, and ultra aerodynamic, and they’re constantly being refined. That doesn’t come cheap.