> Demand would be met with an increase in supply, satisfying all needs for the product and without the "help" of scalpers who sidestep supply-and-demand by artificially creating scarcity to drive up demand for their own profit. This is no help to anyone but themselves.
There's no "artificial" demand. Think about it - the "scalper" isn't going to buy something that they can't sell on, they'd just lose money that way. (Maybe some of them make bad judgements - but they'll naturally go out of business in that case).
> If there's a legitimate demand that will be used, then there's a good case for production to be increased to meet such demand, and all parties who need something would have their needs met.
"Scalpers" improve the quality of that signal and make it easier to increase production with confidence.
> This is also known as cornering the market, a well-known and despised practice
Views on true corners are certainly mixed (there's an argument that it punishes dishonest market makers), but in any case it only applies to buying up the whole supply, which no individual "scalper" does or can.