Barendd Nobeard
Explorer
Enkhidu said:But if they could not expand...
Overpopulation would run rampant, and lack of resources - food, space, etc - would eventually create an environment where a nation's people began killing themselves off, until they reached an equilibrium with the available resources. Overcrowded populations of rodents - notably rats - have shown tendencies to "self destruct" if overcrowded, killing one another for what may seem no reason. Lemmings go so far as to commit mass suicide when populations get too large.
So...
Assuming that the long lived people in control stayed in control - a very likely possibility - I suggest that some sage would eventually recognize the trend and some one would get the bright idea to artificially control population levels. Since you've already stated that people will continue to reproduce at the normal human rate, I figure that those in power would probably be forced to commit murder on a fairly grand scale just to maintain control of the situation.
This might take the form of mass religious matyrdom against a foreign power, or sacrifice of the frstborn male, or extermination of one or more ethnic groups. No matter what, it would be messy, and would definitely be evil in D&D terms (not to mention the real world - I know I would place them all firmly in that catagory).
Hmmm, maybe that's why the quick breeding Orcs and Goblins behave the way they do?
You can also think Logan's Run. If nature or culture can't control the population, the government will at least try to do so.
In LR, not enough resources exist, so everyone has to die at age 30 (in the film; 21 in the book). In the movie, the authorities even devised a very impressive ritual ("Carousel") that supposedly gives everyone a chance at rebirth. It's just a lie; they're killing people to prevent overpopulation.