When the buyer pays and ebay receives funds, they email the seller and instruct to "Ship now". Seller ships the item, ebay has the money, ebay releases the funds to the seller when the buyer has received the item and is satisfied. It is simple and seems to work. As a seller, I had to patient about my money. On the other side, as a buyer of a high-end bicycle, I would not want it any other way.

They must have more lenient funds release policy on smaller items. You will get your money back from ebay. As a former banker, all I could think of is massive amount of money they have piled up somewhere from lagging payments on all those transactions. They daily investment of those funds provides a strong source of revenue.