I imagine that the lack of capital in developed countries (having invested it all in poverty-stricken countries) would cause massive inflation, so people cut their spending significantly. Then, the post-poverty countries would have no market for the products produced by their industry, being dependant on the developed countries for their exports. So, basically, no-one would have any disposable income, countries would have very little trade, but we'd all be equal.
'Make Poverty History' sounds all nice and good, and various people (especially celebrities) use it to improve their image by promoting it. I'm sure there are lots of commited people to this, but in short, it ain't gonna happen. World economics just doesn't allow it.