The numbers were the projected deaths if we did nothing. However the death rate in countries that did not lockdown has been no higher than in countries that did, so the projections, which were based on irrational assumptions, were hopelessly wrong. The lesson there is that when a momentous decision that will inevitably involve trashing the economies of the world’s largest economies must be made, it has to be based on facts, not asssumptions. The facts are that the kill rate of COVID — 19 is little different, actually lower but not significantly so, than that of seasonal flu, which nobody has been screaming alarmist prophecies of doom about.

Update: sorry I should have included a link:
Algorithms Are No Better At Telling The Future Than Tarot Cards Or A Crystal Ball