Monopoly Is "The Game" For US Auto Manufacturers

Now, isn't it telling that in Japan, a country with half the population of the US, there are no less than 12 automobile manufacturers. If the US is the home of Free Enterprise, what are the reasons that there are only 3, truly American, auto manufacturers? When something is profitable, as is the auto business, where are the new, innovative, auto companies? It would seem that either Americans are not too bright (with the trillions of capital sitting around), or Free Enterprise doesn't exist in the US. Monopoly seems, to me, to be the game plan in the US auto industry. With no real competition how can GM lose?
Lord Howard Hurts