The purchase receipt price is not updated in the supplier for purchase price. It is recorded in the inventory transaction history related to the ARRIVAL and then into the invoice for the supplier. But if you have not reviewed and captured the prices using an analysis of the Last Purchase Price at some point (we do it annually), there is nothing that will update the Supplier for Purchase Price. That is a manual process that should be done by the Buyer responsible for the Supplier or the Part Type or some other mechanism.
If you’ve been running for 5 years without this information being anything but 0, you have much bigger problems I would assume.