It's like this article was written by a high schooler.
The Planet Money folk unashamedly try and explain economic current affairs and stories as simply as possible. It's essentially their self professed raison d'être and they do a good job of it.
Quibbling about the the accuracy of their simplified examples is missing the trees and the forest.
This serves as a good reminder that you will be swiftly punished on HN for making a comment that doesn't add value.
In my defense, I didn't miss the trees and the forest. I was merely pointing out that the story was dumbed down, as you put it, "as simply as possible." And replying to a post pointing out their overly simplified math. Seriously, implying that 1 x 1.8 = 2 isn't even back-of-the-envelop close.
However I did enjoy learning about how the Real came to be.
For most uses, like prices of eggs, it's close enough.
However, I do keep one non-virtual slide rule around just to whip out and show the kids now and then. Nice mahogony base, teflon slide, the works.