This seems to be an unfortunate aspect of human nature, linked with the desire for power and status, and goes on everywhere. It is worse when authoritarian governments deny the poor a political voice, or when rich nations use their bargaining power to drive down the prices they pay for products from developing countries. Some people think that the massive debts that poor countries have been allowed to accumulate are a form of exploitation. Colonialism often led to the draining of a country's natural resources towards the wealthier colonial powers. Lack of resources - some countries lack good farmland, plentiful fresh water, minerals or sources of energy.
New technologies can help, provided they are affordable and realistic for the context.
Competition for increasingly scarce natural resources may well cause future wars. Natural disasters - drought, floods, volcanoes, earthquakes. Some of the world's poorest people have little choice but to live in areas subject to regular natural disasters. In emergencies they need aid, fast. It is not surprising that poor people clear forests, overgraze grasslands, and are unwilling to spend money on preventing pollution, all of which increase their problems in the long term.