Any attempt to make an argument of this sort in the current panic is being seen as insensitive and met with outrage (“you don’t care about me/someone’s parents/grandparents”).
If the consensus ends up being that we need to put an 18 month hold on all activity and spend trillions of dollars to extend the lives of a few hundred thousand octogenarians, this will be a mistake that resonates for generations.
Also, the current policy being pursued isn’t a simple “spend x, save y lives” trade-off. An extended period of isolation will not only have economic effects (greater poverty, on average, will reduce life expectancy for many), it’ll also result in a higher incidence of mental health issues and suicide. Children will have their educational development severely disrupted. When the calculus on this policy becomes clear, it could be possible that we end up trading many millions of years of aggregate future life to save a million people who’ve already lived very full lives.