Part of the whole thing is that they truly brought about their own ruin because that's what happens when dragons fight each other. Everybody dies, including the dragons.
They are their own worst enemy. I have a theory and I won't mark it as a spoiler since it's a theory that we'll likely not prove since GRRM is never going to finish the damn A Song Of Ice And Fire books. Anyhow, my theory is that book Dany will die in the quest for the Iron Throne and Jon will eventually take it just in time to unite the realm and lead them in a battle against the Night King. But I believe Jon will die while defeating the NK and with him will go the last of the Targaryen line. Every Targ will be dead by the end of the book series, IMO. The prophecy that has meant so much to them was also a warning of their end.
I hope the planned show of Aegon's conquest really happens, incidentally. I'd love to see the great Balerion the Black Dread in his full glory.
That would be cool. If I could get any story -- books, show, anything -- it would be the Doom Of Valyria. I want to see it at the height of its glory, full of dragons and then see it fall into destruction. What caused The Doom is a question that's never been answered. I think that would be really interesting to explore.
