In light of the fact that the store owner just lost his home and insurance in California is ridiculously expensive, I think you could consider the fact that he's losing his ass as a good reason to give the guy decent money for what is bought.
Most retailers don't look at markup, we look at margin. We have our expenses and that determines how much we need to make in order to avoid losing money. If we need to pick up what we buy from a distributor, 15% profit means we can lose money just by driving there, going through the process and driving to the job or back to the shop. If it's shipped at no charge, it makes more sense to just stay put. 50 points is doubling our cost, but the expenses still come out of the profit/add to the cost, so the fact that someone has a B&M location means they can't match Amazon and still make enough to survive unless they'll also install it and sell accessories. Sometimes, it's easier to buy some items from Amazon and have it shipped- it's usually faster than having it come from the distributor and there's no guarantee the distributor even has it, which I ran into when I needed a Bluetooth receiver that works over a long distance. I looked for one, ordered it at 11:30 AM and it was at my house at 7:30 that evening. I went in and installed it before 9:30 AM and the facilities manager was amazed that I could have it in and working so fast. That impresses people and that gets us a few brownie points.