It does not make any sense to require an actual title certificate to sell an MV due to differences in State laws, and laws outside of the U.S. As Clinto mentioned, Georgia does NOT issue titles on a vehicle older than 1963 unless it already has a title. Several other states have similar rules. From what I understand, all states have to accept a valid vehicle transfer from another state. For example, if a vehicle registered in Georgia (valid registration without a title) and is subsequently sold in State B where titles are mandatory, then State B is required to issue a title to the new owner for the vehicle.
If we want to go down this road, what makes more sense to me is to require certification of ownership of the vehicle, vehicle parts, or other items by the seller. In many cases scrapped vehicles, and major portions of vehicles, are sold without any kind of paperwork. Some of these 'paperless' vehicles are later salvaged and restored, sometimes after changing hands several times.
It is the Purchaser's responsibility to know what is being purchased and the applicable laws. If one doesn't know, it is a simple matter to find out.