User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-174.52.196.175-20130527223109/@comment-4009941-20130528003634

Their was a war that made them lose all their tech and the ones who won left it all behind to prevent such destruction from happening again.

And since then the hunters guild took control to make sure no more species would go extinct through conflict or over hunting to preserv their world so Monster Hunter as bloody as the series is, is actualy a very ecology considering world especially the Wyverians since they are the guild masters and focus their efforts on understanding their world more before causing and destruction to habitats.

So the ruins just sit abandoned and monster nest filled.