Barack Obama had a parting shot for his successor this week. A day before Donald Trump predicted he would be “the greatest jobs producer that God ever created”, the outgoing US president appeared like the ghost at the feast, warning of “the relentless pace of automation that will make many jobs obsolete”.

It is at least possible that both will be proved right. Automation has been a constant for decades, and the latest advances in robotics and artificial intelligence all but guarantee that the pace will accelerate. But timing is all. For companies and their investors — no less than for politicians — the key question is not “whether”, but “when”.

For society at large, the pace of automation will determine how easily the displacement of workers can be handled — and whether the political backlash grows worse. The pace is equally important for the companies trying to push the latest robots and smart machines into the real world, and their investors. Few are in the position of Google parent Alphabet, which has taken the long view on bets like driverless cars — and even Alphabet these days has a new sense of impatience about when it will see returns from “moonshots” like this.