How do you count the impact of economic disruption on people? Even on the lower end, you should count fractional loss of life for people forced into survival mode, the stress, etc. You also have to count knock-on effects on people who become homeless, have a bad childhood affecting their entire life, etc.
If you are so inclined, how do you count the dip in births during the bad economy? That is 80+ years of life expectancy each, whereas the GP is over-estimating the life expectancy loss from COVID, I think the average age of the dead in Italy, after overwhelming healthcare, is over 80.
Then, on the higher end, economic collapse of the Soviet Union reduced life expectancies so much that that probably destroyed more life years than hypothetical COVID epidemic ever could, all by itself; before you count the above.
The year of life estimate of $10M is also preposterous. If I gave you a choice of living to 85 with average wage lifetime earnings, or 84 with the same +$10M, which would you take?
That's 30 million years of life without a lockdown. In the U.S. a year of life is under $150k, so that's an upper "value" of lockdown of $4.5T
U.S. GDP is 21T, so a 25% drop in GDP caused by a lockdown would not be value for money.
"How can you equate money with life saved"? Ask that when nobody is uninsured.