No, bicycles shouldn't be licenced. One very important thing that noone has failed to mention is this. Any vehicle that fits the crieteria to be licenced must also carry uhhhhhhh Liability insurance. That's the law in the majority of states. It applies to motorcycles, motor scooters, and even electic scooters that children drive.
You would be required to purchase and have proof of liability insurance before a licence would be issued. This law will never be passed because bicycles are not motorized vehichles. If however it does become law for licencing of bicycles for public roads and highways. You will have to purchase liability insurance.
As previously stated Motorcycles, motor scooters, and even electric scooters are required by law to be licenced and insured. Bicycles are getting a free ride here. They have the right to ride on the highways, however they don't have to be licenced or insured. Although I don't believe that bicycles should be licenced, Bicycle riders should stop whining about traffic. Since there not paying a cent for insurance or licence plates.