Like if you remember those old bike lights, that got powered by the wheel spinning. That means the wheel spins a bit slower because some of the energy goes into the lamp. I'm sure we could make a modern version of that to slow bikes down, if we tried.
Comments
Point is, you can probably find a way to slow bikes down, if you tried, while keeping aerodynamic gains and advantages of having higher power similar, just at a lower base line.
Attached to the back wheel
1980s