Infections don't matter.
There, I said it - now let me qualify it.
Infections don't matter when virulence is such that disease doesn't overwhelm health system capacity or cause significant mortality. This is reflected in outcomes with common colds and seasonal influenza.
Which demographics have seen the highest hospitalization rates, longest hospital stays, highest ICU admissions, and most deaths from SARS-CoV-2? The 65+ age demographic. The 65+ age demographic represents about 16.5% of the US population but 81% of COVID deaths.
What is more difficult to achieve and causes more social and economic harm for nonmedical intervention of a virus with a estimated IFR of less than 0.4% - isolating 16.5% of the population, or 100% of the population sans "essential workers"?
That isn't to say the 14-64 demographic wouldn't experience some severe disease and death...but the incidence of it would be such to not overwhelm health system capacity (which was the entire point of "flattening the curve")because you don't have a bunch of seniors filling your hospital beds for WEEKS at a time.
But to the point of "protecting the most vulnerable" and allowing the the other 83.5% of population to basically do our normal thing and circulate disease...that ship sailed a LONG time ago and ain't coming back. Instead, we've lengthened the period of the pandemic by "flattening the curve" to buy time toward vaccines, and are now vaccinating these higher age demographics first in an effort to harm reduce while vaccine supply is scarce.
We can argue the merit of 'lockdowns' over the last year until the cows come home but that won't change what happened - we need to be eyes forward as to what's happening and what's coming. Kids need to get back in schools ASAP, economic restrictions need to be further eased, and many younger people (say, those in the 18-55 range especially) need to stop being completely irrational about their individual risk from this virus.