The funny/sad thing about the Amazon soil is its incredibly poor nutritionally. Because there's so much rain, many minerals and nutrients get washed out. In fact, poor soils often result in such high biodiversity.[0] Which means when they slash and burn to grow soy, they only really have a year or 2 where the soil can support that. Afterwards all its good for is cattle (if that). But its so plentiful and demand is so high for beef and soy that we keep doing this

[0] https://www.youtube.com/watch?v=mWVATekt4ZA