The meaning is that Brazil should be a more successful country. Great location, favorable demographics, lots of natural resources, peaceful neighbors, large population, mostly stable government. But it just never quite becomes successful. But in could, in the future! But that's what people also said in the past.
Somewhere I read that around 1900, Brazil had the same GDP per capita as the United States. And that was the peak of Brazil.
I'm not trying to pick on Brazil. I have a favorable opinion of Brazil and its citizens. I hope that Brazil proves the economists wrong and becomes the country that it can be.