Low volume, and everyone who isn't a big company just buys clones.
If you are a company or care about reliability, you have to get the OEM version but hopeful you amortize it over thousands of crimps.
My guess is that they need to be cut using EDM (slow) and need expensive CMM machines to make sure the resulting die shapes match the tolerance.
I know you're probably referring to OEM hand crimping tools that cost on the order of 500€/$, but even decent quality non-OEM tools (e.g. Engineer PAD-11) aren't exactly cheap. Though, I hear IWISS ones are usable if you're on a budget.
The generics are pretty cheap, but I guess it's a relative matter. I got a PA-20 for $35 on Amazon and it works with all the Molex micro-fit I've thrown at it. Each crimp takes much longer than if I had the $500 purpose-built tool from Molex itself, but I do so few it doesn't matter.
The higher end (Daniels / DMC) are very precise tools that you should calibrate with a go/no go gauge. If you handle one you can see why they are fairly expensive - everything is precise, heavy, and without slop and must remain so over thousands of crimps.