It's really not. By and large the former colonies are today's "shithole" countries. Not a coincidence. Everyone is in the same race, working hard to win it, but some start way behind (and others start way ahead).
Yes, they were wealthy once. Just like S. Dakota was. Until the price of oil fell. S. Dakota was then propped up by safety net spending funded by our wealthier states. A country like Venezuela has no such out.
The US consisted of former colonies as well. So, there goes that retarded argument.
But, they do have an out. Why didn't someone in Venezuela simply invent the internet, cars, Apple, TV, radio, the microwave, electricity, create a different industry, massive biotech company, the lightbulb, gum, ice cream, soda, the electric motor, computers, iphone, Facebook, Google, ecom, ebay, paypal, watches, modern manufacturing, etc?
Or, why didn't Venezuela simply copy US tech and manufacturing like China or Japan?
Do you really think that drilling for oil is the only thing that Venezuela is capable of doing?