I would argue that, at the moment, economic development of former colonies is happening considerably faster than development in the former colonizers. And the evidence agrees with me. Take China, for example. Per capita income there has grown from $89 in 1960 to over $9000 today (constant 2018 dollars), a 100x increase. Over the same period, US per capita income grew from $3000 to $60,000, a 20x increase. The number of nations mired in desperate poverty drops every year, and the number of nations improving their economies rapidly grows.

The gap is closing.