It's the kind of incuriosity that comes from the arrogance from believing you're very smart but actually being quite ignorant.
So it wounds like one of those guys took their misunderstanding and built and sell tools founded on it.
They continue walking until they come across a second pile of shit. The second economist turns to the first and says “I’ll pay you $100 to eat that pile of shit.” The first economist takes the $100 and eats a pile of shit.
Walking a little more, the first economist looks at the second and says, "You know, I gave you $100 to eat shit, then you gave me back the same $100 to eat shit. I can't help but feel like we both just ate shit for nothing."
"That's not true", responded the second economist. "We increased the GDP by $200!"