"But it's all sold out." It's easy to sell out less of a product that's more popular than your worst popular product. Of course they're not meeting demand yet. Neither has their competition. This confirms that the Series X is more rare than the PS5/PS5 Digital but yet its street value is less. Why is that? Simple. The PS5 is in more demand.
Not much of a surprise really considering Microsoft apparently didn't start production until late Summer. It's why XSX can say they have "Full RDNA2" and PS5 can't.