Given the proverbial black hole present in Dragon Lore in TES most of this is just heresay and opinion. The only thing we really know is that dragons make very few appearances in TES, and as such, in order to hold true to lore, this must continue, and if it doesn't there better be a brilliant explanation why it isn't that doesn't come of cheap.
That being said, other then the practically non-existence referencing and rumors, the only other thing we have to guess about the behavior of dragons is from other RPGs... I don't want a cheap rip off, I want originality, so accepting them on that basis would be irrational. However, that being said, Dragons in several versions of D&D are all but extinct, and for that matter whatever ones remain are rumor and heresay. Dragons that are seen or have stories around them are always very young and quickly killed with great haste followed by fleeing, and the majority of larger Dragons and older Dragons frequently use taking on the form of another being, usually humanoid, as a means of hiding away.
Beyond that the lore in TES is so intricate you could draw a million different little conspiracy theories as to how precisely Dragons fit into the story.... However, I recall very few major revelations brought about by the main quest that had enough evidence in the TES lore before the events took place to be predicted. Their stories are almost always beyond the ability of the community to figure out via research because they add a number of new elements and triggers that we could not possibly have been aware of until they start giving us hints or previews of the game. As such I hope there's a lot of evidence out there that we are just blind to, and that someone truly dedicated to figuring this out with a brilliant mind, and ingenuity could figure it out, because that adds to feeling of "Why didn't I see it!", when we don't figure it out but its revealed through the plot line and sums up a ton of unexplained Lore. However, this is unlikely, and most of the information, and originality will likely be created to specifically tailor the plot of TES V while maintaining the feeling.
We are dealing with creative game designers here, not experts at mystery reverse engineering
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