I'm not sure if i'm missing some lore or something, but I feel like the Oblivion Crisis could've been much easier on Cyrodiil(and the whole of Tamriel) if the Imperial Army had done something to help the town guards destroy the gates. I can understand not having a large standing army because of the golden age, but not having one at all? that seems pretty unbelievable, even for The Elder Scrolls.
So, what do you think about this, am I missing some info, or does this make sense?