I expect you'd find the same dynamics despite adding some positive externalities to the transactions. Depending on how large those externalities are. The nice thing about this example is the code is there for you to modify and test your theories.

A good simulation tries to pare down the system, not getting distracted by other mechanisms that don't change the basic dynamics. For example, it'd be more realistic if the transactions were partially parallelized, but that wouldn't change the analysis much.