[joe_the_user]

The development of Quantum Field Theory is a good example where >10 people all collaborated to come up with a framework that integrated the viewpoints of multiple theorists with radically different approaches, rather than every new contributor forking a personalized version of the previous theory.

Sure, I hope I was clear that I don't ten theorist (or ten programmers) collaborating is impossible. I would simply say that collaborating has an extra cost to it - and a competitive academic world, any cost needs some degree of payoff. This makes extending a mainstream theory advantageous but not so much less-known theories.

And Quantum field theory had the advantage that the experiments for demonstrating it's truth or falsehood were relatively straightforward. With AI, the question of a theories truth is more debatable.