I'm honestly not familiar with Arena and Daggerfall, but Morrowind, Oblivion, and Skyrim all focus on defeating some sort of world-ending apocalyptic threat.

I'm kind of curious what would an Elder Scrolls main quest would like if it took a different direction. New Vegas and Cyberpunk came to mind to me as stories that didn't solve some "fate of humanity" problem and instead focused more on local politics or personal survival.