The fact that people can immediately flip a knife for a huge profit means the price is below market value (longer term profits I have no problem with...they're betting the knife will appreciate and the opposite could happen, so I don't think there's anything wrong with that).
I'd say this is more an indicator that demand exceeds supply, but it is being artificially inflated too. The same thing happens with concert tickets. People who have immediate access (these days I have seen computer programs used to automatically buy tickets) to the tickets buy them and then resell them at a profit.
You might be able to stop this sort of thing with tickets, but doing so with a material good is hard - a buyer has right of first sale. Once they own it, they can do as they will with it.
I'm afraid that the only solution I can see is either increasing production, or Busse and the company store controlling the flow. The latter solution requires a lot more effort than offering them all as a batch. Since Busse is a family business, I doubt it's feasible.
The best solution is probably increased production from the shop. If knives can immediately resell for much more, then there is a demand.