Not so odd, me thinks.
In the age of discovery and colonisation, the British along with other civilised nations of the world, took full advantage of the spoils of discovery.
The British were more successful because they not only moved into these countries and took full advantage of the rewards that could be gained by trading etc, but they also ploughed back into the less developed countries most of their expertise, railways, irrigation, dams, roads, schools etc,etc.
After the British moved out, all these things went into decline. Take Zimbabwe for example the rich farming land that the British farmers cultivated, have now reverted back to dry, dusty un-fertilised earth.
Looking back into history this little group of islands we call Britain became the most powerful peoples on earth, just like Romans centuries before. But that is history, today is different, we don't need certain countries to trade with, one trades with whoever has the right goods at the right price.
So what are these 'comforts we enjoy now' thanks to the Commonwealth?