Tesla has built its business on being a pioneer. It was the first automaker to produce electric cars that were fast, fun, and desirable, with battery ranges measured in hundreds instead of dozens of miles. Now, it’s pushing into another new, less welcoming, frontier. Elon Musk's company just became the first automaker to lose access to the full $7,500 federal tax credit designed to spur the adoption of electric cars. As of January 1, its customers only qualify for a $3,750 credit.