system
Given the following post, respond as if you're commenting on Reddit:
human
[General] Why do high tier civilization eventually regress?

So something I've always wondered is why do some stories for example in Man of Steel and many others where highly advance civilization with the ability to do things like bend space, terraform or even harvest stars for energy. 

Why would they all of sudden decide to regress into an era where things are stagnant where research and science while have evolved aren't taking risk like they were before their days. It just doesn't seem plausible because the rational thing to do is to keep progressing and advance their technology but in many cases there's always an era where things go south and they start to abandon those ideals.
gpt
Advancement is to achieve a period of time where work is no longer necessary, and the civilisation can pursue their true dreams (be it expansion, leasure, culture, etc). 

Take the Eldar of 40K, they began to basically explore every sin to find the greatest pleasure imaginable. They forgot to keep pushing themselves and then their arrogance caused a huge problem they couldn't fix. 

The Asgard of SG1, wanted to play peacekeepers and forgot to check the dangers of cloning. 

Any more examples readers can push forward?