You are 100% right. In nature, the fitness landscape is not fixed, it is dependent on the co-evolution of other organisms at every scale. So the computational m

You are 100% right. In nature, the fitness landscape is not fixed, it is dependent on the co-evolution of other organisms at every scale. So the computational model is too simple to be a reliable guide. But in this case, if you assume constant fitness over some delta-t (kind of like calculus), I think it's still a plausible explanation for the divergence phenomenon in particular. Just a hypothesis, though, for sure.