. You pay for it into the escrow system and then I send you a house brick via a courier. Once you open it and discover I have scammed you, we have no way to know/prove who is lying .. So who gets the money?

In India Amazon delivery people needs an OTP after the buyer verifies the item. Only then the delivery is marked as completed. I think now they are also taking the photos of the item delivered. This is applicable only in the case of high value items.