Because the third parties don't really care enough. They just want to make the sale and get paid. Where is the incentive to setup and manage a queue for someone like Target?
If they had a queue, I'd add myself and they'd get a guaranteed sale from me. Since there's no queue, I just have to wait until they're in stock somewhere. Might be Target, but it'll more likely be somewhere else.
it works as a market differentiator - if target is the only one that implements a purchase-before-restock queue, they get guaranteed purchases from people who are price sensitive and not time sensitive
that no one is doing this... maybe it has something to do with the fact that it would show up as a liability in accounting until they deliver the product
