Mainland China needed to pour its greatest talents into civil and military projects. Looking back from the privileged present, this strategy has been effective though it might have been overly streched. But, if you were the one in charge, would you be able to predict the future any better?
I have been trying to bring people here to see that the keyword for understanding today's world is "colonialism (globally by the west)", without much success. If one sees it, one will see China's singular role as well as importance in the forming of the more fair world, and why it was neccessary for China to build its strength that way. China would have remained weak had it produced one Einstein but no Yuan longping. So it was much more sensible to have no Einstein but to have 100 Yuan longpings.
HK and TW and Chinese elsewhere have been without these constraints.
Mainland China now is finally good enough to withdraw these constraints bit by bit. Things will look good.