I don't think US industry has ever dismissed South America as a rounding error. They get the huge economic importance it has. Rather, we've had some feet dragging from unions (and to a smaller extent a little xenophobia, but I think this is really really small when it comes to Free Trade Agreements). Give the US another decade or two and there will be a full on American Free Trade Agreement.
I worked on Terespondo, a search advertising company focussed on SA from 2002-ish to 2006. We were thirty dorks who happened to speak the language, and we captured 65% of a continent-wide market. Why?
- MS AdCenter didn't get multilingual support until 2008 or so.
- Google Adwords required a US credit card until 2004 or 5.
- Overture (Yahoo) were idiots.
It's gotten much better in the last ten years.