That's not what he is saying. His header is: "There is no such thing as a 10X developer (without a 10X environment)." It's p->(q is possible), not p->q.
Ultimately though I feel like the flaw of the argument is the idea that there are all these great developers sitting around constrained by their environments. Great developers would be constantly frustrated by poor environments and would either change them or move on. What really happens is that these poor environments attract poor developers and nothing changes.
Certainly no company can go out and hire and rock star or a ninja or whatever and save their organization if the organization is terrible. It could work, and it has worked, if the organization is willing to change. But more than likely said 10x developer would just move on when they couldn't affect the change necessary to produce 10x the output.