Why would you attack an empire at full strength? Don't blame the argonians for making a sound tactical decision with their invasion.
We are not the agressors here, we wanted to liberate our people from houses Telvanni and Dreth(I think)
The Dark Elves are just jealous because they can't war for their lifes.
Ever since their great Nerevar left them, they've only been going downhill.
And when he came back, through Nerevarine, things were finally starting to look up.
AS SOON as Nerevarine left Morrowind for Akavir it literally exploded, I wonder why?
Not even Vivec, who despite not being a god anymore still had great knowledge,wasn't able to properly lead his people and fell to the Daedric invasion,which in turn led to a chain of events that ensured the destruction of Vivec city and Vvanderfell,as explained in the books.