u/Adjactive_Noun

Just told Robert the truth when he was on his death bed. A royal proclamation from an alive Robert would have held more weight.

Like, they lost their dragons 150 years before they lost power, the political situation could have reverted to the pre conquest status quo, another dynasty could have overthrown them, some of the kingdoms could have broken away…

But their rule was taken for granted to such a degree they stayed in power another 130 years despite having no real way to enforce it.

And when they were finally overthrown, it took 20 years of Aerys being an absolute lunatic and practically begging the realm to revolt before he finally provoked a rebellion.

And even then Targaryen rule was seen as so legitimate that the new ruler was chosen based on his relation to them. Robert being Eggs great grandson and all.