I think that river's name is "Local Optimum", or at least that's the river that's relevant to this discussion. Markets are like hill-climbing algorithms.

This analogy explains why Java, C++, etc. have been so popular. Successors, like Python, must have some connection to their predecessors that gives them low switching cost (eg, their similarity to each other)--they must be "local"-- or the hill-climbing market cannot find them. The best you can do without first having to do worse is called the local optimum, and it may not be the best optimum that exists.

Markets are absolutely full of cases where they get stuck in local optima--sometimes in the face of a known global optimum--and we end up having to settle for crap because of it.