Capitalism isn't a magic antidote. Nor are all iterations of it successful. It really depends on the government keeping corruption under control, keeping monopolies from forming, keeping regulatory capture from occurring. Also, capitalism is just an economic system. There's also political systems, legal systems, financial systems, military systems, all sorts of other government functions.
Capitalism is actually working pretty well in Asia. China is doing tremendously better since they introduced some capitalism into their socialist system, creating a mixed economy. Their growth has lifted a lot of people out of poverty. Other Asian economies have performed very well. Look at Taiwan, Singapore, South Korea, and (at least prior to Chinese takeover) Hong Kong.
Latin America and Africa have a lot of complex problems, many stemming from years - or even centuries - of colonialism, military conflicts, social issues, endemic corruption, bad economic policy like "printing money" and trying to spend their way out of inflation, thereby creating hyperinflation, etc. Expecting an economic system to magically fix all the incredibly complex and even seemingly intractable issues in a society is quite unrealistic.