Milo Rau, once the enfant terrible of continental European theatre, is a little less buoyant these days. The Swiss theatre-maker has done something he says he explicitly hates: he has cancelled a guest. “Yes, we hit a wall,” he says. “But at least it made the wall visible.”In his capacity as the artistic director of the Wiener Festwochen theatre festival, Rau, at the end of last month, first invited, then disinvited, the American tech billionaire Peter Thiel. The Austrian weekly Falter called it a fiasco.Since taking over the Vienna festival in 2023, Rau has turned one of Europe’s major multi-arts...