"Native tools" ? The people who make and use these knives have used them daily for survival fo hundreds of years, if not thousands, yet they have survived and prospered. I have seen them forge blades and harden/temper them with great care. As for tangs, some are much larger than commercial knives that I see these days, and I don't see shapes which are stress raisers. And tangs are not hardened so you don't have them snapping off if you baton a blade. The blades are edge hardened, like Japanese swords.
Yes, they don't have the advantage of current top-notch metallurgy, but they make stuff that works. I'm willing to bet that they can do more with a knife than you can on a day-to-day basis. Don't dis "natives". They will surprise you.