There was a change in the world, which went largely unnoticed - sometime in 2013-2017 the global number of infants peaked, never to recover.
Those 20% would just figure that there's no need to have children when you can just focus on yourself and go largely extinct within a generation, replaced with some people from the higher tiers, but not nearly enough to make up for those who weren't born.
This actually has been happening without AI for a while now, but I imagine technology would accelerate the process.
There was a change in the world, which went largely unnoticed - sometime in 2013-2017 the global number of infants peaked, never to recover.
Those 20% would just figure that there's no need to have children when you can just focus on yourself and go largely extinct within a generation, replaced with some people from the higher tiers, but not nearly enough to make up for those who weren't born.
This actually has been happening without AI for a while now, but I imagine technology would accelerate the process.