There's an argument for scalpers, but it's more subtle. Companies want immediate sales and to be able to say they sold out. Scalpers let them do that by taking on some of the risks themselves. And it ostensibly allows people to make a time/money tradeoff between waiting in line or for later supplies versus paying more.
See my reply to vkou. This is exactly how scalpers make the situation better, by creating the availability of the choice to make a trade-off, where before there was no choice but to compete on latency or luck (which is fine for many consumers, but consumers vary in their ability to compete on latency and in their valuation of the trade-off).
Consider rationing when there's a food shortage. We can either feed everyone (At reduced rations), or we can let some people pay more, to get more food, at the expense of letting others starve.
Isn't it great to give people the choice between destitution and starvation? (Or, in the case of the poor, between starvation, and starvation.)
There's a reason rationing is common in times of hunger.
I was using this example to demonstrate that optimizing for [choice/wealth] does not always result in better outcomes. Just as the parent post posits that optimizing for first come-first serve does not always result in better outcomes.
I understand why a concert venue would be happy to get guaranteed income from scalpers, but this does not hold for consumer devices.