Based on… why do you think that?
I'm basing it loosely on how much Ashley Wood co-owner of the 1/6 scale company ThreeA has said injection molds cost. He could very well be lying but I have also heard similar prices from other people in different industries that use the same process ala DrQ2 above. The Matty Collector people have also said similar things about the costs of molds. They might have even stated an exact number on cost. I'd have to look it up.
I fully admit that I don't have any sort of decent knowledge of production but if you're going to say I'm wrong straight out I'd like something to back it up other than just "I know".
I ran across this through some quick Googling, no clue how reliable it is but it seems to line up with everything else I have ever heard. Basically that injection molds cost hundreds of thousands of dollars each.
https://www.custompartnet.com/estimate/injection-molding/