Why can't somebody copy this?

Copying the software is easy. Occupying the position is not, because the position is a shared representation that other people have already implemented.

Three barriers compound: conforming implementations already in production, scientific credibility that takes years to acquire, and a governance path that makes the model adoptable rather than captured.

This is argued, not demonstrated. A large platform with distribution could bundle an adequate layer, and the competitive analysis says so explicitly.