There are two problems, even internal contradictions, with segregating the elderly and letting others return to work. The first is fairly well known. When you run the numbers, as the British did, you find that a lot of young people would die. If we return to work too quickly it could easily happen that 20-40% of the US population gets COVID-19. Suppose 20% of the population gets it–that’s 66 million people. And let’s suppose the death rate is on the low end because healthy, young people get it rather than the elderly, say half of one percent, .005, then we have 330,000 deaths of healthy, young people.
Moreover, the numbers I just gave are conservative and don’t make a lot of sense because if 330,000 die then the hospital system is going to be overwhelmed and the death rate will be higher than .005. An internal contradiction.
The second internal contradiction is less well known. We probably can’t segregate the elderly because the more young people get COVID-19 the less realistic protecting a subset of the population becomes. In other words, the premise of the segregation argument is that we can protect the elderly but that premise becomes less plausible the more COVID-19 spreads but allowing it to spread is why we were locking down the elderly. An internal contradiction.
Are there some scenarios where all this works out? Probably but I wouldn’t bet on hitting the trifecta. The lesson of COVID-19 is that like it or not we are all in this together.