Collectibility is a function of supply vs demand. As the guy behind the products and marketing for Upper Deck in its early years I can tell you that it was exactly the use and abuse of product that led to the shortage. When people make knives just for collecting they have to be very careful they don't overproduce or lose their mojo.
I look at Busse and Strider and I can see why people want them but I think they are already drilling pretty deep into their narrow base. Its easy to drive perceived rarity and perceived quality (because people don't actually use collector knives) with hype but my experience people ultimately like to collect things that make them smile when they drag them out and they should be inherently interesting or unique products that were produced in much smaller quantities than initially perceived.
I always like to do a numbered release of a product and only market it through quiet channels. BUT I make that product a great deal. We sold the DPx HEST with a signed hardcover book and certificate for list price which made it a better deal than the production model. That makes people go Whoa damn. I should have snapped that up. When I am dead and gone I think people will appreciate they have something that links the knife to the person.
Its also a generational thing. People tend to buy the things they wish they had when they were young and couldn't afford. So yes the very fact that people love and USE their RAT/ESEE and DPx knives will make them collectible but not for a while