This recipe is a fantasy. And it is not what has happened in any population except maybe a few groups of medical workers who were treating patients in outbreak

This recipe is a fantasy. And it is not what has happened in any population except maybe a few groups of medical workers who were treating patients in outbreak zones. But it's a fantasy because of how slow the controlled spread would have to be. Some of the best medical systems in the world have been pushed into chaos with less than 1/1000th of the population infected. This level has increased the mortality rate by two to ten fold, depending on age group (with younger groups seeing a much greater increase). If each 1/1000th of the population takes weeks to be infected and recover, then this plan will take at least a decade to reach the levels of exposure required for herd immunity. And by that point, the virus will likely have mutated into something that those previously infected can catch, destroying the benefit of the plan. The only solution right now is total quarantine. Even maintaining infection rates of 1/1000th of the population is going to require that.