Buy direct from busse, wait a couple years and sell them for a couple hundred dollar profit.
I wonder about this. I have bought and sold about 12 or so. I currently have rotated, sold, and whittled back down to 4 core users.
I have had more success with direct buying (or proxy buying from a show).
You can, with a bit of study, and care, and investment of time, get a bit of an increase on even new released knives.
I am not sure that the value of the knives produced today will have the huge increases in price that the older models enjoy. They are producing a much higher volume these days than those knives of 10-20 years ago.
I have a few users, that sold for an increase. Some that I just made a quick decision on purchase and jumped on when they were listed at a great price. I had to know that they were a great price and jump. As there were several "I'll take it" that I beat out by less than a minute.
You see a lot of instant flippers that try to sell immediately after acquisition. Some times they find a sucker, some times they complain.
Other times, they go on Ebay and greatly exaggerate the qualities of the knife ("Insanely rare Busse...............well, really it is one of thousands of that exact model...........maybe........because we don't know production values...........and I have no idea..........").
I will never make any real money at my knife hobby. I buy what I like, and when I get bored, I sell it, and buy another knife I like. I don't have the money to "invest" in knives. I have enough disposable income to buy a few higher end knives, and enjoy them.
Right now, I am at more of a maintenance phase. I have about all the money tied up in knives that I am likely to devote to them for the foreseeable future. I rotate them out occasionally. Selling one or two here and there to fund new knife projects.
I have done well to grow that fund a bit, by occasional luck. But I am not a profiteer or flipper of knives. I have never bought a knife with the purpose of selling it. I have jumped on knives thinking if I don't like them, I can sell it instantly and more than break even.