Real world logic or at least theoretically possible logic has been used in fantasy for some time. The eberron setting of D&D is cold-war steam-punk with some multi-national corporations. Yet, it has decent logic and logistics behind it. Heck it had a magical nuke go off even.... more or less, no one knows exactly what triggered that tragedy, but still.... Anyway, the fall of Luskan also makes perfect sense in the Forgotten Realms setting as did the fall of Edificent Library... can't remember if that was cadderly's original library or the cathedral he built at the end of the cleric quintet. Even athas/dark-sun setting makes sense because of both the continued presence/influence of primordials, absence of deities, AND the presence/discovery of defiling magic.
But D&D was built to be able to handle real world and theoretical logic. Meaning it is under different settings and guidelines then this rp. So comparing and desiring it to be in the same setting and frame as D&D is unfair for the owner and Co owner of this rp. So in over all you can not apply your logic for you did not make it. Now I will give that rps are built off of the rpers but those rpers would have no base without the owners who made the story and settings. So therefore you can not apply D&D logic and theory to it for this is not D&D if you had wished for the complexity and down right headache inducing complexity of a logic based D&D like rp you should create you own or find one. But please do not try to transform someones elses work into a D&D like proxy.
I'm not saying this rp should be more like d&d, rather it should follow d&d's example along with many other great rps and stories. Some of the best stories are those that speak to truths of human existence, some of the oldest being things such as tragedy and comedy. In theory tragedy shouldn't be popular, but it is because everyone suffers to at least some degree in their lives. Likewise, comedy is popular because it provides an escape from the mundane and ordinary, yet its premises tend to be within the bounds of believability at least in the beginning. Furthermore, in many popular fairy-tales there is an element of struggle between the main creature and some monster or threat or hindrance either internal or external or an external manifestation of an internal fear or hindrance. As a result, if the rp had been more balanced in terms of situation, I probably wouldn't have asked for an underdark. I would've been happy on the surface, but because the surface was so stable and peaceful and established, a new region that was chaos 'down the rabbit hole' so to speak(have yet to read that book) into someplace that is vaguely familiar with female dominance socially, but also more dark and twisted than the surface. A place where the dark of the surface would be considered a light shade of gray and where pure light is impossible to survive unless it is hidden away and kept secret as a source of internal strength, though a person would have to lie at least to survive. That challenge, that chaos, that illustration of both anarchy and law&order seeming to exist both simultaneously seems kinda refreshing at least from the surface.