The key would have been to allow everyone 60 and under to continue normally unless they have other risk factors. The consequences of a case for most in that age group aren't too bad, less than flu for most. Older folk and those at risk could isolate and take other precautions.
No economic shutdown, no 40 million unemployed, no $6 trillion spent, far fewer bankrupt businesses, and vastly fewer long-term consequences. I hope we learn from this, it was an EXPENSIVE lesson. 20/20 hindsight is a wonderful thing.