The economy of every nation primarily lies in the hands of the government. If the government aren't doing their job then even the entrepreneurs will find it very difficult to survive.
Entrepreneurs, investors and resources are very important for any countries growth but with a bad government the best entrepreneurs, investors and human or natural resources usually go out of the country and this is why many talented and gifted nation are still behind economically.
You're not far from the truth, for every business to thrive, the government has to create enabling environment, their should be easy access to loan facility should incase those establishment needs it in the future, in different countries of the especially the developed countries why businesses grow easily is because of the way their government run the affairs of those countries, the loan facilities are accessible, the interest rate too is is not heart breaking that's why in most developed country, you won't experience insufficient of food or consumables, farmers have easy access to loan facilities infact any business can get a loan for expansion, government look into many things that can make businesses grow but in some countries it is the opposite that happens, why many countries are far behind as you said is because of the set of leaders they have.