Your cost-benefit analysis is incomplete: Covid-19 can cause long-term lung damage even in the young.
Apparently, there was some significant recovery of lung damage in the aftermath of the 2002 SARS-CoV-1 outbreak (Pulmonary interstitial damage and functional decline caused by SARS mostly recovered, with a greater extent of recovery within 2 years after rehabilitation. [1])
This doesn't change the fact that this has to be accounted for if you want to play the numbers game.