The very best blades seem to come about when a knife maker gets obsessed with perfecting their favorite steel to work with.
A good example mentioned earlier was the Onion D2. He has worked a basic tool steel into a virtual super steel. Before his stuff, I wouldn't have trusted a D2 blade that was much longer than 4.5 inches but I would trust him to make a machete out of it.
It is all about the heat treat.
Just like McDonalds and their chicken nuggets. Tough as a golf ball yet made from what was previously liquified chicken parts.