Looks like you are assuming that the west - England, France, Spain etc conquered other countries to improve those countries. In reality, the primary motivation was to get economic leverage against the competing powers at the time. And often times, this is done at the expense of the economic well-being of the people of the conquered countries. For example, the British Raj destroyed the budding local textile industry and trade between India and other European countries, Persia and Turkey.
If not, what makes you think it would be any different with Africa?
Most of the examples you stated have to do more with people fearing a "not so good life" - old age, reduced mental and physical capabilities etc., not necessarily death.
What Nominull said. Let us also not forget that it's not just the wealthy and the powerful that choose to use new technology (availability is another issue that I'd think should be squarely in economics court. May be Prof. Robin Hanson already has some posts on that?). Often times, it's the people who are generally enterprising that adopt new technologies because they see efficiency gains in doing so.
I've been reading Elizer's posts for about 2 months now and I am completely hooked! I can't find enough time to catch up (although I work in IT and I do have free time ;-)
I fail to understand how compartmentalization explains this. I got the answer right the first time. And I suspect most people who go it wrong did so because of the assumptions (unwarranted) they were making - meaning if they had just looked at the question and nothing else, and if they understood basic gravity, they would've got it right. But when you also try to imagine some hypothetical forces on the surface of the moon or relate to zero gravity images seen on tv etc, and if you visualize all these before you visualize the question, you'd probably get it wrong.