I thought it would be cool if you could pre-order one through a local library. Here, at least, getting a library card requires visiting in person, so scalpers would have trouble getting multiple unless the librarian were in on it.
I don't think that sort of relationship between manufacturers and libraries exists, though, and I'm not sure it should.
Why would any retailer implement this? Oh please don’t repeatedly come back to my site.
As far as how, there are dozens of things companies could do. Require a credit card verification, don’t allow digital credit cards, don’t ship to PO Boxes, don’t allow VOIP phone numbers, require an account with the retailer, do browser/machine fingerprinting, don’t allow purchasing on a VPN, scan the secondhand market for barcodes and ban people, require linking social media accounts and check for matches, don’t allow different billing and shipping addresses, require phone number verification, and on and on and on.
If retailers wanted to make sure it was one customer per video card, they could absolutely, trivially, do it.
But why would they? That’s a lot of commotion, and things people would probably get upset about. It will lead to less traffic on their site. And, at absolute best, they will get the exact same revenue.