This Apple situations has a good analogy in car industry history: the Ford Pinto.
Speaking of car industry, Apple might have gone through a cost-benefit analysis reminiscent of the Pinto Memo.
https://en.wikipedia.org/wiki/Ford_Pinto#Cost%E2%80%93benefi...
Ford converted the likely injuries and deaths that would be caused by an unfixed issue into a dollar amount, and the compared that dollar amount to the cost of fixing the flaw in every vehicle.
Apple might have done the same sort of cost-benefit analysis: as in, just let the throttling cover up the flaw so the phone doesn't abruptly shut off, and then we only have to deal with the lower cost that comes from any complaints about performance, from those who notice.