An rapid upswing in immediate demand, when it takes time for other firms to gear up, radically benefits existing manufactures, which are typically fairly limited for any given generic.

Nonsense. Aspirin is a generic drug. Generic drugs are widely produced because a) again, anyone can make them so b) profit margins are very thin. Thus, c) the only way to profit is through volume.

HCQ is a very common generic drug; it is given prophylactically to those traveling to malaria areas, for example. Any COVID19-driven short-term shortages are going to affect the manufacturers' bottom lines in relatively small ways. Again, I ask: What evidence is there that Trump or anyone else had a financial incentive to untowardly push HCQ?

I assume you are not denying that they did push it - so, I want to ask in return: for what other reason did they (specifically Bolsonaro and Trump) push it in this way? Given that it was not backed by science.