How do you understand the Cakkavatti Sutta? https://suttacentral.net/dn26/en/sujato

How could humans have lived 80 000 years in the past? And how could we live 10 years in the future, with people reaching sexual maturity at five, when life expectancy is constantly increasing?
I have never read the sutta. Bhikkhu Sujato wrote:

The Dīgha contains truly mythic texts in DN 26 Cakkavattisīhanāda and DN 27 Aggañña. These set forth a myth of origins, replacing conventional creation mythology with an evolutionary account of how the world came to be the way it is. In these stories, human choices play a critical role in how the environment evolves, and in how it will all fall apart. The Aggañña depicts climate change quite explicitly, showing how human activity affects the plants, the weather, and the natural ecosystem of which we are a part (see also AN 3.56).
The mythology is essentially cyclic. There is no absolute beginning; just another turning of the wheel. Thus even when the world falls apart and civilization collapses, there will be a new renaissance, far in the future, and ultimately another Buddha will arise. He is named as Metteyya (Sanskrit: Maitreya) who in the early texts appears only in DN 26 Cakkavattisīhanāda. He went on to become one of the most important figures in Mahāyāna Buddhism, and many Buddhists even today still await his coming with hope. Yet DN 26 is not taught in order to encourage devotees to dedicate themselves to Metteyya, but to illustrate the impermanence and uncertainty of our lives. The Buddha always taught that we should practice as best we can to understand the Dhamma in this life.
The Long Discourses: Dhamma as literature and compilation