By the fifth sentence of Twenty Thirty, Albert Brooks already looks like a modern-day Nostradamus. At an 80th birthday party in the 2011 novel, everyone looks suspiciously good, due in part to “a new weight-loss drug” that “works almost 100 percent of the time, in everyone.” Then come the computer watches, the self-driving vehicles and a generation of young people furious at their elders for living so long and consuming so much of the country’s wealth. But the prediction that gave the director of Lost in America chills was the one about a Jewish president. Related Stories In the novel,...