He has $111 billion burning a hole in his pocket. He admittedly made a mistake not betting on Jeff Bezos and Amazon ( AMZN ). He has dabbled in technology via a high-profile bet on Apple ( AAPL ). He knows industrial companies better than any 30-year-old investment banker. He knows the electric car industry by way of a September 2008 investment in Chinese electric car maker BYD Auto. He has acknowledged that autonomous Tesla semi trucks may kill his railroad Burlington Northern (he could get in on that technology and ship parts via rail). So why shouldn't Berkshire Hathaway ( BRK.A ) billionaire investor Warren Buffett not buy all of Tesla, give Musk some shares in Berkshire and leave him as CEO and call it a day?