Is it really true that money can’t buy knowledge?
We can ask the most knowledgeable person we know to name the most knowledgeable person they know, and do that until we find the best expert. Or alternatively, ask a bunch of people to name a few, and keep walking this graph for a while.
This won’t let us buy knowledge that doesn’t exist, but seems good enough for learning from experts, given enough money and modern communication technology that Louis XV didn’t have.
Caveat: ask each person to name someone they personally worked with.
Hard to get right, but not sure whether it’s harder than knowledge investment.
Wouldn’t have helped Louis XV. We might need infrastructure in place that would incentivize people to make themselves easy to find.