The answer you are looking for is that centuries of imperialism and resource extraction leaves those countries impoverished and unable to function when the power shifts.

For that to be true, what was life like before Europeans came to South Africa, Brazil, India?

There where no railroads or running electricity. They didn't appear to operate any automobiles or advanced machinery either.

When the Europeans were forced out of these countries, it's more logical to assume they were handing them a Civilization that the Natives had no experience with, as opposed to the idea Black & Brown people already discovered these things but somehow "forgot" how to use them. And even that is still strange.

South Africa was not depleted in 1994. It was still a functioning country, even under sanctions and global boycotts. But when Apartheid ended and Blacks came to power, several National Companies began to file for bankruptcy.

Like their National Airlines was founded in 1937, but today it's now broke.

https://apnews.com/article/virus-outbreak-africa-business-airlines-south-africa-b6c4196ece3070025a7728d4e90606e1

South Africa’s state-owned airline has suspended all its operations as it struggles to raise a bailout of more than 10 billion rands ($591 million). South African Airways, one of the country’s state-owned enterprises face allegations of corruption and mismanagement, filed for liquidation and bankruptcy protection in December last year. The business rescue team assigned to manage the company has announced it has failed to raise the money needed to implement a rescue plan for the airline. The suspension of operations may be lifted if the government comes through funds it has promised.