What you’re describing (in the too much fresh blood scenario) is very similar to usenet’s eternal september — the older users need to train the new guys into th

What you’re describing (in the too much fresh blood scenario) is very similar to usenet’s eternal september — the older users need to train the new guys into the “culture” (which will also evolve with their presence). But if there are too many new users, they can’t be trained fast enough. By the next year, it’s new users training new users, and if it the population keeps growing too quickly, it becomes an endless cycle — whatever culture develops has less than a year before it evaporates