Elon Musk wrote within hours of buying Twitter that he “didn’t do it because it would be easy”. That statement has proven to be one of the few certainties about his ownership of the influential social media platform, which has tipped the business into a state of constant flux, with advertisers slashing spending, user numbers down, regulators circling and the staff at less than 50% of what it used to be. From dumping a world-renowned brand to attempting to overhaul the company’s business model, Musk has changed Twitter more in the past year than any other executive in the 16...