Two words: Big Pharma.
There are untold billions to be made with an “approved” Covid-19 vaccine and BP is NOT going to allow a common, inexpensive drug ace them out of it.
This also explains the absolutely apoplectic response to yesterday's Front Line Doctors' pro-hydrochloroquine press briefing.
I also read an article last week talking about Covid testing, and how it's nothing but a scheme to peel money off the government, AND US.
Since you don't get timely results, its only use is to line the pockets of the testers.