The New Big 3: Toyota, GM and VW
Since it's more relevant to view autos from a global perspective than a national one, the new Big 3 are Toyota, GM and VW, in that order.
I predict that, with the quality gap narrowing, GM or VW will overtake Toyota as the world's largest vehicle manufacturer. Why? As quality equalizes, it is no longer the powerful differentiator it once was. It's a buyers' market, and Toyota has shown less success in making it's vehicles aspirational. The new Corolla is an excellent example of design mediocrity. It's a good product, but falls short of being exceptional. The Focus, Mazda 3 and Jetta seem like stronger entries; more fun and exciting compacts, or, at a minimum, less dull.