This is the story WSB is telling:
There are two PS4s. Alice has one, Eve has one.
Herbert knows that with the PS5 release, the price of a PS4 is going to fall from $300 to $100.
So, Herbert borrowed Alice's gadget and sold it to Bob for $300. He planned to buy it back off Bob when the price fell and give it back to Alice. So far so good.
Herbert got greedy, though, and then borrowed it back off Bob and sold it to Charlie.
Now, Eve looks at the situation and posts loudly on the internet "Herbert owes two PS4s. There only are two PS4s, and I have one. So Herbert has painted himself into a corner: he needs my PS4, and I can charge him whatever I want. Sure, he can have it. For 3 grand. No, 30 grand. I can literally make up numbers at this point."
It's a good story.
However, Herbert ignores her. He knows he's messed up, but he also knows she's wrong. He doesn't need her PS4 in particular. So, he goes to Charlie. "Hey mate, that PS4 I sold you, could I have it back? I'm really sorry, something's come up. I'll give you $600." Charlie says "sure".
Then Herbert goes to Bob and says "Hey mate, here's that PS4 I borrowed. But actually, do you think I could buy it off you? I'll give you $600." And Bob says "sure".
Then Herbert goes to Alice, and gives her the PS4 that he borrowed.
And Eve is left shaking her head in a disappointed sort of way.
What happened, at core, is that Eve thought Herbert owed two PS4s, and so the number of physical PS4s was some sort of hard limit on how he could fix things. Instead, he owed two PS4-transactions. He'd sold a PS4 twice, even though it was the same PS4 and wasn't really his to sell. So now he has to buy a PS4 twice to balance it, but it can be the same PS4 that he buys both times.
The most important lesson for us is, be careful when Eve says that we can buy her PS4 for the low low price of £1000 and Herbert is guaranteed to buy it off us for whatever we ask. We might wind up just giving Eve a grand for an outdated bit of tech and have nothing to do with it except put in in the cupboard.
There is of course some sense in which the story is true. Herbert does need to pay over the odds to fulfil his obligations. But he doesn't need to pay Eve. He needs to pay whoever will give him the best deal. If Eve and Charlie agreed that they won't sell for less than thirty grand, he'd have to pay one of them thirty grand. But that's illegal. And without a binding agreement, it's in Charlie's interest to be reasonable so that he gets the sale rather than Eve. So Charlie gets the sale, and Herbert doesn't have to blow £30,000 on a cupboard filler.