Two weeks ago 11 firefighters on the department that I retired from tested positive. 1 had symptoms that he thought were from seasonal allergies. 10 never developed any symptoms, all now test negative. None needed any type of medical treatment. At least in this case your assumption your assumption is off by a large amount.
I have a friend who is a supervisor for the TSA at SeaTac; the number of employees they had infected and those with and without symptoms were almost identical.
I suspect the only reason the firefighters were tested was because of their profession. Like those in Santa Clara, they normally would not have been tested, but developed antibodies regardless. One in 10 of those who get the virus will get some symptoms, mostly mild. In a New York study of pregnant women, 4 of 33 got some symptoms. One in 66 will get sick enough to need to go to the doctor and get tested for CV-19. What I mean is of those who become sick enough to go to the doctor and get tested, only 1 in 10 will need hospitalization.