Comment by imtringued

You have noticed the problem with humans. They don't like modeling decay. So decay is simply ignored and assumed away. Meanwhile biological systems model decay. There is no obsession with growing forever. People's height is limited by nutrition and genetics, nothing else really.

If humans actively modelled decay in their society, their civilizations would last as long as ancient Egypt. Ancient Egypt was conquered by Romans aka outside forces. Meanwhile the Roman empire collapsed from within.