It sounds like a good idea, but in reality, the sport of road cycling is and always has been extremely heavily dependent on bicycle manufacturers. You could probably make an argument that professional cycling exists mostly for the purpose of selling bikes. At the moment, five of the eighteen WorldTour teams (they're the top level teams) have names like BMC Racing Team and Trek-Segafredo, and I don't think they'd be very happy about everybody riding unbranded bikes.