Sharing his predictions on the economy less than a month ago, Luigi Di Maio, the Italian deputy prime minister, believed the country was on the cusp of an economic miracle akin to the one enjoyed in the 1960s. “During that period we built highways, now we can build digital highways,” he enthused. His comments were met with derisive laughter. There was even less to laugh about on Thursday when figures revealed that Italy, which is saddled with a public debt…