I really like your ideas. Maybe these dragons are tied to some kind of natural force, that had it's ebbs and flows across the ages. In the past they were abundant, but times have changed and a lot of the dragons have gone dormant or withered away. They know their time will come again eventually. The ones that are still awake will find their natures become less grounded, which can cause strife. With my dragon it causes a restlessness that eventually leads him to live amongst humans.