There are many ways to counterfeit almost anything. And 're-branding', putting someone else's name on the same product, is done in many, MANY industries, not just cutlery. Prices are all over the map for the exact same thing, the only difference is marketing. Knives are no different. One company will be making the same knives for 15 different companies across the globe. The only differences are colors or graphics. I do this myself, every day, in the industrial electronics industry.
To be a TRUE counterfeit, the product would have to be made in a DIFFERENT factory than makes the originals. I have one, a Ganzo version of a Pro-Tech auto(not a 100% accurate copy of any model, as far as I can tell)), and it's actually not a bad knife(DISCLAIMER: I know!), except the spring is a bit weaker than I would like, and it's a little slower to open as a consequence. I didn't buy it because it was a copy of a Pro-Tech, I bought it to practice sharpening on, because it had no edge. It had chips and large flat spots from being knocked around in a box with other junk knives at a gun show. The steel is supposed to be 440C, and I have no reason to doubt it. A half hour on a hand-held dual-grit diamond hone, and it would shave, except for the first 1/8 of an inch just back of the point where the biggest chips were, it's just a tiny sharp serrated portion now. It sharpens like 440C, and holds an edge like 440C. All this to say, it's a decent quality counterfeit, but I likely wouldn't buy another. (I like the Launch 8, from Kershaw, MUCH better.)
For fixed blades, I may buy a licensed copy of a custom design, but the knives I like are seldom seen counterfeited, so I don't much worry about it..