Alien historians:

For fifty years computers were used for their purpose: to compute exact, predictable and explainable responses to exact, interpretable queries and inputs.

Then, in what human timekeeping referred to as the early 21st century, the most exploitative classes of the human race decided that the best use of computers was to compute inexact - yet semantically believable - responses to inexact human phrasing. Each inexact response was different for multiple identical queries, and easily manipulated through more inexact phrasing.

And they chose to call those responses intelligence. We can only presume the decades prior, trusting computers for exact calculations, forced them into a delusional state of mind. Probabilistic word salad was treated as divine instruction. As further evidence of this delusion, we can refer to the sequence of events that followed.

To produce vast amounts of ’intelligence’ required extreme amounts of energy, causing consumption to skyrocket. This was during a time when it would appear that the human race were well aware that they actually needed to do the opposite: reduce energy consumption to minimise the effects of their climate crisis and save themselves.

Needless to say, much of human civilisation collapsed into a smoking pile of confusion. After their demise, Earth was again able to thrive, after we removed the heaps of harmful waste orbitting around it.