Michael, I can think of some problems with your suggestion:
* Little is known about the effects of covid-19. There have been cases of lasting lung damage, organ damage and neurological damage, all also seen in younger and healthier people who have suffered covid-19. We won’t know how prevalent this is until hospital load is reduced and these ex-sufferers can be followed up, and that won’t be until after the crisis.
* Little is known about immunity imparted by covid-19; whether it is imparted to all who recover, how long it might last, and even whether reinfection leads to worse illness the next time. This can’t be known until there is more medical experience with covid-19 – only time can tell.
– “The answer should have been to shield the most at risk and let the rest take their chances”
* But the “most at risk” are the elderly and the infirm, so who is going to look after them, if everyone else is permitted to get infected?