In the history of the automobile, there have been iconic sets of wheels, but only two cars that could truly be called groundbreaking. The Ford Model T — and the Toyota Prius. The Ford Model T created the mass-market motorcar. And the Prius perfected it for the 20th century. After two decades of dominance, the Prius might be heading for decline, as hybrids are surpassed by all-electric cars. Still, the Prius remains the Prius — homely, sincere, and an unlikely blockbuster.