system
Given the following post, respond as if you're commenting on Reddit:
human
[Attack on Titan/Shingeki No Kyojin] How does such a corrupt/lazy government and society grow out of an apocalyptic event?

Those who survive in these times are born of those who managed to build three layers of walls, the outermost with a 480km radius, in the midst of the extermination of their species by a far more powerful adversary. Surely such people would not be the kind to spawn a system of useless lords and cowardly warriors?
gpt
First off, the walls were not built, they were discovered. The surviving population took refuge within, and has conducted some minor detailing, but the walls themselves were found largely as they are.

Second, the fall of the outer wall was the first breach ever. For the most part, people just lived inside the walls for a century with only the Rangers actually encountering Titans. 

A century of no real fighting, and no real concern, is more than enough time to breed an ineffectual military and a corrupt government.