Well surely the point is we do want to go about our business as soon as practicably possible? The tests provide the only route to open up that path.the issue with this is that with these tests we’ll start to see far more people going about their business because they’re immune. How then do you manage those that aren’t immune. Many of these people will either start to go outside simply because they can....or in the mistaken belief that everyone they encounter outside will have already had the virus.
The people you want to isolate are not the ones who have had it or those that don't have it.
It's actually the ones that currently have it you want to quarantine into a herd so that they can contain the virus and no longer spread it. Once you identify those, that will then help to rapidly curtail the spread.
I think the stats of the tests held so far were out of 90,000 tests only 8,000 people tested positive. Meaning 82,000 were negative.
It's not a large enough sample but if you apply that to the nation you can then begin to understand that the vast majority of people sat at home right now is because of the few.