Is it due to lack of resources, or due to lack of excavation equipment? If you look at a map of the world from, say, a century or two ago (not sure how far back you'd have to go here) the North Sea wouldn't be identified as an oil-rich sea; the Middle-East probably wouldn't have been particularly prosperous either. OK, I'm not entirely sure about the reliability of that information, but you see my point.
Also, the reason for the poverty famine disease and thirst is, funnily enough, global warming. Im sure that tens, or hundreds of thousands of years ago the Sahara desert was fairly lush - all that happened is that the rainforest has receded to such an extent that now all that's left is a big hunk of sand. Whether it's down to human interference or not is anyone's guess. Obviously, we had no part to play in the early stages of desertification, so you can take that for yourself.