Among the trials and tribulations of the plague years, there was a silver lining. In late 2020, with the approval of Covid-19 vaccines, and into 2021, as the jabs worked their magic, techno-optimism began to spread. If people could develop life-saving inoculations in months, why couldn't the world move out of its low-growth, low-productivity slumber?

Firms could embrace digitisation as never before; the shift to working from home could allow people, free of office gossip and draining commutes, to work more effectively; before long there would be vaccines for every disease imaginable. Governments promised to spend big on science; companies outlined juicy R&D plans.