daiku,
from my understanding, modern tool steels, particularly the excellent Swedish and German top of the line varieties, are special alloys capable of being hardened to hold a fine edge, while still maintaining enough flexibility to allow the entire tool to be made of a single chunk of steel. The result is that the tool can be made much faster, and doesn't have the potential for weld failure. Gransfors Bruks manufactures their tools this way, if you want something to go by. All German tool manufacturers that I ever ever purchased tools from or seen their tools make them this way too.
So I would say that if they use a good quality alloy tool steel(such as the mentioned Elmax) then there is no need for lamination. It is redundant, and introduces a potential for flaw and failure.
In the 1800's, they did not have high alloy steels capable of this. In addition, what tool steels they did have were very expensive. And so you have welded pieces because in that era it was cheaper to do, and more reliable since the steel was in fact brittle -more or less straight carbon/iron or at times low alloy.
older tools have the bulk made out of non-alloy iron. I have a few of these tools (one a 250 year old German axe) that I love. Iron require less maintenance than steel, because the carbon alloy in steel makes it attractive to oxygen, causing it to rust. Iron will form a brown or black patina, and then will stop rusting under normal conditions. steel however will just keep on rusting.
