You've assumed he will pay full price to replace the goods though, which is highly unlikely.
Let's assume he paid £30 for the goods he was selling at £70. So he'll only need to pay £30 to replenish the goods he lost, which will get him back to where he started if he again sells them for £70. Alternatively you could say he's lost the profit he would have made on those goods, meaning he'll have lost £40.
Reminds me of a story from my accountancy days, where I was working for a mate (Mike) who'd set up on his own and we had a shopkeeper client. Something had happened - a flood or a fire iirc - that meant some or all of his stock was ruined and unsaleable. He had a policy he'd taken out on Mike's advice which covered him for loss of profits, and which he naturally claimed on. We had his books so we could calculate that figure. But he got really annoyed when he found out it would only replace the profit he would have made on the stock, not the retail value.