Every oligarch knows the best way to bump your tumbling-yet-still-obscene wealth is to promise something outlandish and ludicrously unobtainable

This suggests that a reaction from consumers who dislike Mr Musk’s antics are only one reason for falling sales. An updated Model Y, Tesla’s best-selling vehicle, has just gone on sale. In preparation Tesla ran down inventory of the old model, crimping supply. Customers doubtless held off purchases until the new car was available.

Tesla’s stock has dropped by nearly half in three months. Even so, investors are still debating whether Elon Musk's electric-vehicle maker remains overpriced.