Maybe in the new generation the same % of people will decide to not have kids and populations in developed countries will continue shrinking geometrically maint

Maybe in the new generation the same % of people will decide to not have kids and populations in developed countries will continue shrinking geometrically maintaining the present trend. This line of reasoning is very interesting to ponder though. The black plague in Europe made survivors materially richer as they were able to take possession of what was left behind from the deceased. As there's less and less people to compete for stuff, the existing younger populations will be richer, thus giving them an incentive to focus on leisure and reproduction. Then there would be a cycle were the sharp decline in population, plants the seeds for the next big rise.