well here is my two cents (I see I'm about four years late for that lol)
The Thalmor's cause is doomed from the start.
1) The First thing is that Talos being a god is not even under question by the Scholarly (Or the Priests.) Both by game (Knights of the Nine) and by Lore, Talos is already accepted to be either a god (using the mantella), have mantled Lorkhan, or to be an avatar of Ysmir. he's a god. Nords have been worshipping his equivalent since time immemorial.
2) The Thalmor argue that the Eight are Elven gods and thus real gods, who deserve worship. here's the truth. apart from Akatosh (Who, by the way, was added to the pantheon by Alessia because he needed to please the elves so there wouldn't be another war) all of the Eight are actually Nordic gods.
Kynareth (Aka Kyne), Mara, Julianous (Jhunul), Stendarr (Stuhn), Zenithar (Tsun), and Dibella are all nordic gods, and the Godhood of Arkay is actually under question (What with, you know, him not actually existing as a god until the first era)
The Nords have been worshipping a form of these gods as their own since they left Atmora. what right do elves have to claim kinship with them? (The Ehlnefoy, who were the descendants of the gods, bred both Man and Elf, so No. Elves have no more of a claim to be the children of gods than men do.
3) The Thalmor (And the Empire) claim that the Elves would defeat nords in war, if the Empire wasn't there to lead it.
well, that's utter rubbish.
History check. The Great War. the Aldmeri Dominion attacked Cyrodiil and took over the entire province other than Bruma (which, ironically, was protected by the Nords) and the Empire had no luck in taking it back, until the Nords came down from the Mountains and aided the Empire, and singlehandedly broke the Thalmor control on Imperial City (Btw, Titus was not even in that battle. TES: Legends actually probed that to be false) which led to the Legions (most of them nords by now) pushing back the Elves to the borders and then Titus the Dumbass surrendering a winning war.
However, in the West, The Redguards had a better luck. The race of magic-hating, Warrior humans living in a horrible climate defeated the Dominion and pushed them back to the borders without any help from the Empire.
This alone proves that, if a second great war actually starts, the Empire will, at best, be a crutch. The Nords and Redguards have better chance of beating the Thalmor without the Empire.
4) The Answer to this question: Elven Supremay is a Joke. nothing more.
