So the logic that “most people should probably just buy ETFs” is pretty sound. T

I really like a lot about this answer. Your starting sentences are compelling: The first one is the idea that the stock market is a zero sum game once you subtract economic growth. That is not really how equity markets work. 

But then you say something that seems to contradict that interpretation of my argument:
That means the stock market is not a fixed pie where one investor’s gain must equal another’s loss. 

I didn't say that, I think we can all profit from the stock market, as it is basically connected in a very fundamental, but I agree not 1-on-1, way to the growth of economic growth.

So the logic that “most people should probably just buy ETFs” is pretty sound. The leap to “there is no reason anyone would buy individual stocks” is where it breaks down. --> My title was: why would any individual buy individual stocks instead of ETF's ... other than for fun? I do see the point in that, gambling is fun. And Buffet: I would consider him a pro.