No, it is not quite so. The real wealth and prosperity was to the south, in Bukhara and Samarkand. The territory of (present-day) Kazakhstan was not particularly affected. Some rudiments of civilization were in Kazakhstan in the pre-Mongol era. After that nothing much happened there, there was a steppe where nomads grazed their cattle. I think that's where the history of those you call “they” begins. Great development and industrialization took place only after WWII.