The wealthiest societies today were until recently very religions or colonies of said societies. It was not imperial China that kicked off the industrial revolution but the very christian and quite religious Great Britain. A more likely interpretation of the data is that increasing wealth leads to decadence and undermines religiosity. High IQ is associated with success and wealth. Low IQ countries stayed poor and religious.

Superstition and religiosity are distinctly separate entities. While it is true that both are currently correlated with low IQ I have argued that only the former will be associated with low IQ over the long term and provided reasons why this may be the case. I also highlighted religious groups that defy this correlation.  

What makes you think we will hold onto capitalism? We lost capitalism some time ago. Freedom requires a solid moral foundation to be maintained. Lose your moral foundation and the rest slowly collapses.