Why did the pedestrian's action against the motorcyclist fail in the federal diversity case?

The pedestrian's action against the motorcyclist likely failed due to insufficient evidence of negligence. In a civil case, the plaintiff (the pedestrian, in this case) must establish that the defendant (the motorcyclist) was negligent and that this negligence caused the plaintiff's injuries. If the pedestrian could not sufficiently demonstrate that the motorcyclist failed to act with reasonable care and that this failure led directly to the incident, the claim would not succeed.

While other aspects, such as jurisdiction or state law preemption, play important roles in civil procedure, they do not directly relate to the fundamental issue of proving negligence. The inability to demonstrate negligence is a common reason for the dismissal of personal injury claims, particularly in a federal diversity case where the standard for evidence may be scrutinized closely. Thus, establishing negligence is critical to the outcome of this type of case, making it the key reason for the failure of the pedestrian's action against the motorcyclist.