> In the 1970s there was a huge concern that if proper infrastructure was built, it would cause foot and mouth disease to make its way from South to Central and North America

That's fascinating!

Wikipedia shows that the disease is nearly eradicated in South America:

https://en.wikipedia.org/wiki/Foot-and-mouth_disease

I suppose there still wouldn't be an economic incentive to build a road when there are two large bodies of water on either side?