No, he put it "on sale".
If the stock "tanked" as you say, the drop in price is the same as offering dish soap", "on salr for a limited time only". All you have to do to break even, is sell enough bottles to cover the discount percentage. At face value, this is jusk Musk tasking a tack to talk more people out of their money. Realistically, the dish soap seller has to manufacturer enough extra product to meet the increased demand.
But, I seriously doubt that Wall Street is "going to run out of Tesla stock". So, the drop in price fuels speculation, which in turn would increase the number of prospective buyers/bargain hunters. Which is basic math, since if the stock dropped 10%, you only need 11 buyers instead of 10, to make up the dollar shortfall.
As for the total investor pool, they'll be a little butt hurt by the loss in value of their shers, but the vast majority will still hold onto it, because, "they're certain it will come back up".
We can only hope and pray that will happen. Musk is at best, "a bad little boy", seeing how much he can get away with before mommy spanks him.
Clueless about Covid19, definitely. But "clueless about stock market manipulation, not hardly.