Yes! Success for most Fairs depends on the timeline you're looking at. Even the 1984 World's Fair in New Orleans (which I know I call out in the essay), was considered a failure at the time. Now 30+ years later, New Orleans has a thriving waterfront district that wouldn't have been developed without the Fair.
>over a hundred years later, Chicago is still making money from the economic, social, and infrastructure benefits of its fairs.
Because of the way the economy works, this can be said of absolutely any expenditure anywhere anytime for any reason. If even one project laborer buys a cup of coffee on the job, at least $4 of value then gets sent out into circulation in a way that has been plausibly colored by the construction of the Big Money Pit of 1849.
All expenditures stimulate the economy equally, as measured by the "marked bills" theory. That means the only way to compare them is to evaluate opportunity costs. Spending a million bucks on constructing a big hole in the middle of nowhere, and performing an important infrastructure revitalization, will both put dollars in the hands of laborers, and thereby grocery stores and so on, at the same rate. That's why all of the useful parts of the discussion are on the specific, immediate consequences; the distant consequences are the same no matter what you do.
For example, over a hundred years later, Chicago is still making money from the economic, social, and infrastructure benefits of its fairs.