The marginal return on education spending decreases fairly quickly, but obviously becomes zero at the point by which there are not enough hours in the day/year/decade to cover every single topic that humans know about - no matter the talent or resources available to the student.

> A quick search suggests that the most expensive education in the world is something like $100k.

I have a kid in an American university right now, and a quick search of my bank account statements confirms that there are far more expensive educations in the world.

Some results, sure.

But that list is extremely ambitious. Write a best seller, make a popular game, come up with a truly novel theory, consistently outtrade index funds.

That's top 0.001% human stuff, I don't think you can take just any person and get there through education alone, it takes extreme talent and dedication. There's also diminishing returns when spending on education, it doesn't just improve linearly.

except you are missing the one versus many argument here. sure we could make one human much smarter, could we make endless copies with the same intelligence? no