Are Vast Majority of COVID Cases Asymptomatic?

From studies in prisons in four states comes a remarkable conclusion: as many as 95% of COVID-19 cases may produce no symptoms:

As mass coronavirus testing expands in prisons, large numbers of inmates are showing no symptoms. In four state prison systems — Arkansas, North Carolina, Ohio and Virginia — 96% of 3,277 inmates who tested positive for the coronavirus were asymptomatic, according to interviews with officials and records reviewed by Reuters.
After a recent spike in cases at the Neuse Correctional Institution in Goldsboro, North Carolina, state correctional officials tested all 723 prisoners last week. Of the 444 who were infected by the virus, 98% were asymptomatic, the state’s department of public safety said. …

Similarly, mass testing at two Arkansas prisons — the Cummins Unit in the city of Grady and the Community Correction Center in the state capital Little Rock — found 751 infected inmates, almost all of them asymptomatic, the state corrections department said.

The implication, of course, is that vastly more Americans have had the virus than has been believed. That would be great news, because it means that 1) the disease is far less lethal than was once feared, almost certainly in the range of a seasonal flu virus, and 2) we are farther down the road to herd immunity than has been believed.

For reasons I can’t explain, those commenting on the Reuters story don’t see the fact that the virus produces no illness in the overwhelming majority of people it infects as good news:

“Prison agencies are almost certainly vastly undercounting the number of COVID cases among incarcerated persons,” said Michele Deitch, a corrections specialist and senior lecturer at the University of Texas. “Just as the experts are telling us in our free-world communities, the only way to get ahead of this outbreak is through mass testing.”

But how will mass testing “get ahead of this outbreak?” The more tests we do, the more people we will find who have, or have had, the virus. So what? Epidemiologists say that the virus will continue to spread until a critical mass of us have had it and are immune, a number that probably lies between 40% and 70%. The virus will then more or less die out. I fail to understand how doing millions of tests on apparently well people is going to guide policy in any significant way.