Humanity is entertained by competition of all kinds. The pandemic has shown sports fans will find a new way to cheer and chant and boo. It is sometimes underappreciated how new professional sports is as a dominant cultural phenomenon. For the vast majority of human history, sports has been overwhelmingly played by amateurs. And even in America, it is only in the past fifty years that this professionalized version of sport became a route to wealth. Baseball, which has the longest professional sports history in the United States, illustrates this: the average MLB salary is up an inflation-adjusted 3,000 percent...