The binding constraint on the number of effective organizations is sociocultural, involving motivation, ideas, and willingness to organize talent.
It gets down to deep questions of: "What is the binding constraint on the number of effective organizations that exist in the world?" For any given sector, why is it that number of companies rather than twice that number of companies and so on? It's about motivation, ideas and people's willingness and determination to organize talent and so forth. But these are kinds of more sociocultural explanations.