This is fairly common for a lot of Scandinavian traditional knives. Rust resistance may have entered the equation with modern steels, but the history I am told was that the laminated steel idea was all about strength. A lot of the "old" steels available suitable for making a sharp edge will not be very resistant to breaking or bending, so you envelope the "edge steel" with a more resilient steel.


Traditionally, the steel in the edge does not necessarily have good edge retention - you need to sharpen anyway, you might as well make that process easy and quick. The easy-to-sharp & poor edge retention compromise is surprisingly common in traditional Scandinavian knives.


These days, modern technology and knowledge gives a totally different control over the outcome and a vast array of steels for knife making that a traditional knife maker never could have imagined. Still, the laminated steel is a good design compromise in many circumstances.