But I am telling my children that nobody will take advantage of them if they study and work hard, everything is in their hands.

Well, that depends where you are. If you are in a country that needs to export primary produce, and rich capitalist nations raise barriers to prevent imports of your product while demanding that you remove barriers to their own products, you can work as hard as you like but you'll always drag behind. Meanwhile people in the rich industrialist nation enjoy a standard of living that is not entirely due to "hard work", but also to unbalanced trade conditions like these.