The Simpsons may be headed to Disneyland. Last month, the U.S. Justice Department gave its blessing — some said fairly quickly — to Disney’s acquisition of 21st Century Fox in a deal valued at .3 billion. The approval paves the way for the creation of a mega-behemoth entertainment company, combining many top-flight content brands and two of the world’s largest movie studios whose films all together commanded half of all box office receipts year-to-date, according to Box Office Mojo. “It was an extremely quick decision, particularly when you look at the market share numbers of these firms, at least in some markets, which puts them pretty close to the line,” said Herbert Hovenkamp, a Wharton legal studies and business ethics professor with a joint appointment at the Penn Law School, on the Knowledge at Wharton show on SiriusXM channel 111 .…