They put anything under the table for the sake of their favor and the corrupt officials are just keeping it for their sake. This isn't new to those poor countries and that's why they're having hard time dealing with it and foreign investors doesn't see any potential on it for which, it should be one of the factors that can help them go up.
This is about making riches for children unborn and when they are born they keep ruling because the parents and family have already stolen wealth that they can use to intimidate others and get into power therefore limiting others to gain something from the system. Perpetual representation is the reason resources don't get to grassroots and poverty spread farther. Bad government is the reason that majority have hard times surviving.