Think of the hopes, the dreams, the effort, the brilliance, the pure force of will that, over the eons, has gone into the creation of the Cadillac Coupe de Ville. Bicycle riders would have us throw all this on the ash heap of history. Frustrated truck drivers and irate cabbies make a point of running bicycles off the road. Terrified old ladies jam umbrella ferrules into wheel spokes as bicycles rush by them on sidewalks. And all of us have occasion to back over bicycles that are haplessly parked.
Bicycles are quiet and slight, difficult for normal motorized humans to see and hear.
People pull out in front of bicycles, open car doors in their path, and drive through intersections filled with the things. The insubstantial bicycle and its unshielded rider are defenseless against these actions. It's a simple matter of natural selection. The bicycle will be extinct within the decade. And what a relief that will be.