I like the connection between Goodheart's law and overfitting. However these examples are a reach:

--- Goal: Healthy population Proxy: Access to nutrient-rich food Strong version of Goodhart's law leads to: Obesity epidemic

I'm not sure I believe this one. Exactly who's target is "access to nutrient-rich food" and how would removing that target fix the US obesity epidemic? Is "nutrient-rich" a euphemism for high-calorie? My understanding is that there are plenty of places with high-nutrient food but different norms and much better health (e.g. Japan).

We can and do measure population health across (including obesity), this isn't a proxy for an unmeasurable thing.

--- Goal: Leaders that act in the best interests of the population Proxy: Leaders that have the most support in the population Strong version of Goodhart's law leads to: Leaders whose expertise and passions center narrowly around manipulating public opinion at the expense of social outcomes

Is this really a case of "overfitting from too much data"? Or is this just a case of "some things are hard to predict?" Or even, "it's hard to give politicians incentives." It'd be interesting if we gave presidents huge prizes if the country was better 20 years after they left office.

--- Goal: An informed, thoughtful, and involved populace Proxy: The ease with which people can share and find ideas Strong version of Goodhart's law leads to: Filter bubbles, conspiracy theories, parasitic memes, escalated tribalism

Is "the goal" really a thoughtful populace? Because every individual's goal is pleasure, and the companies goals are selling ads. So I don't know who's working on that goal.