I have just returned from Canada, which seems to share Britain’s new-found obsession with veganism. There, chains such as Burger King and KFC are offering plant-based alternatives to meat-based meals. Five years ago could anyone have predicted this? True, vegetarianism has been growing for many years, but did anyone foresee its most extreme variant rapidly ‘crossing the chasm’ to go from an oddball niche to a standard lifestyle choice?

The ‘chasm’ is that mysterious and often impermeable barrier all technologies and behaviours must traverse if they are to make the critical leap from being a weird minority interest to an unquestioningly...