I view Tesla as the best bet for a completely new American car company in a long time.
The U.S. Big Three have been around for eons. After World War 2 Hudson and Nash were hurting, merged to form American Motors, and went bust. Packard and Studebaker were hurting, merged, and went bust. Kaiser/Frazer tried, and went bust. De Lorean tried and got in to all sorts of trouble. Nobody seemed to be able to launch a new car company and make it work.
Tesla, on the other hand, seem to have cracked it. They're selling all the cars they can make. I see lots of them around here (Vancouver).