re: Which nation that is currently not "first world/wealthy", will be in 20 years or so?

Yes, but they have had a boom in economic development of the rainforest since their policy in the 1960s similar to the US policy for claiming land during the frontier era.

Essentially anyone who wanted to could claim vacant land in Brazil as long as you could demonstrate economic use of the land.

This is where the "save the rainforest" campaign came from. They were proposing to build a transcontinental highway in the 80s that would have opened up the whole of North Brazil to economic development. The enviros managed to stop it.