Ah, so the real world requires trust but despite what the blockchain says. I get what you mean now but you can still make it a lot easier.
Using your example, you could write a contract such that: you buy an item for X dollar amount, the contract holds it in escrow, waiting for FedEx to confirm receipt of the package and a deposit of Y% of X into a rolling insurance fund from both FedEX and the seller. At this point, if FedEx fails to deliver you’re fully refunded out of the insurance pool and the seller gets their money back. If they deliver, FedEx gets 90% of the insurance payment back, the shipper gets your payment, and they split the seller’s premium as a shipping fee. If the seller never drops off the package you get your money back.
You could even throw in a return period where a third party can confirm whether a bad package is eligible for refund.
There are obviously holes in this haphazard scenario but the big picture is that there’s a lot of stress that can be offloaded to a truly unbiased 3rd party, even if you can’t achieve full trustlessness in real life.