The crisis at the US vaping group Juul that contributed to the collapse of a possible US$200 billion (S$276.3 billion) merger between Altria and Philip Morris International is another example of a fashionable disrupter of a traditional industry faltering. WeWork has shelved its initial public offering and Juul's US$38 billion valuation is evaporating.

But Juul's troubles, which led to its chief executive being replaced last week, are not merely a financial shock to its investors, including Altria. The company's misbehaviour could cause public health damage by sparking a broad US crackdown on the best alternative to smoking so far, apart from giving up nicotine entirely.