You're noting a pattern too?
Well then, where is the show of causation of the huge birth rate of Mexico (7 children per woman) leading to an economic boom compared to the economy of the USA over the same time period?
Or any huge birth rate being associated with any economic powerhouse modern nation?
Correlation is not causation - but there is an obvious and overwhelming correlation between nations that are basket cases and super high birth rates.
While the super low birth rates of moribund socialist states are to be avoided - I fail to see the appeal of the ultra high birth rates in any particular real world example from any nation within the last hundred years.