Theoretically, if the price were to fall far enough, only ten Steem Dollars could be "too many."

This is absolutely true. It is a problem that needs to be kept from getting out of control, and you can't rely on the price being high at all times to solve it. The reality is that crypto markets are highly vulnerable to price drops including extreme price drops and what needs to happen is: a) not creating too many SBD just because the price is high at the moment (which was done last summer), and b) reducing the supply aggressively or at least slowing the rate of increase as the price starts to fall (which was not done last summer).

I agree with you the promoted tab leaves a lot to be desired. That said, I still visit it to find good posts and I suspect I'm not alone. I find posts that someone is willing to spend money to "promote" as being of generally higher than average quality. Not 100%, but it is a decent indicator.