Surely you're not comparing the need for healthcare in LA with west Africa?Then thousands of people don't really show up at free health fairs.That could be because the availability of high quality medical services are ready available in LA. In Africa, there are only 2.3 healthcare workers per 1,000 people. In the US there's more than 24.8 per 1,000 and there are 25% less communicated diseases to deal with.Have you noticed that doctors without Borders will go to Africa but not Watts. You don't see these doctors treating the sick in American slums.
http://www.who.int/whr/2006/overview_fig6_en.pdf