Even so, there are just as many models of "mid-size" trucks for sale in the US as "full-size". Ford has something like 5 different sizes of trucks, and size #3

Even so, there are just as many models of "mid-size" trucks for sale in the US as "full-size". Ford has something like 5 different sizes of trucks, and size #3 is their best seller. If a size #0 suddenly showed up at the dealership, there is no reason to believe that it would destroy the market for size #3. But there is every reason to believe that it would be popular!