This means they have had to build roads to transport goods, which is much more expensive than transportation by water.
This is a terrible geography for the Brazilian economy: No navigable rivers plus rugged terrain means extremely high transport costs. You can’t transport anything by water—which is 10 to 30 times cheaper than by road.
So after clearing, leveling, fertilizing, and sowing their rugged fields, Brazilians had to communicate them with the world, so they’ve been spending billions painstakingly building roads.
This river basin wants to unite, and whoever controls it is the most powerful country in the region. That’s why Argentina, Brazil, Uruguay, Paraguay, and Bolivia all went to war several times after their independence from Spain and Portugal: They all knew that whoever controlled the region would become wealthier.