You might think many HN visitors are "foolishly naive," and I would respond no: HN is instead full of too many people who believe that they're somehow less naive than everyone else.

I'm not an experienced trader, but I know about the efficient-markets hypothesis and that analyses such as this one are often "priced-in" to a certain extent. But when the market opens on Tuesday, AAPL is going to go up or down. "Underpriced" is a measure that can only be fully assessed in retrospect -- if AAPL goes up on Tuesday, it was underpriced tonight.

You're right that there are tens of thousands of large players with billions, all trying to screw each other over. I believe that 100%. But there's still room in there for Joe Normal to buy some AAPL stock. If his hunch is correct, the stock will go up in value and he'll make money. Individual people still make money trading stocks, and it's "naive" to think it's solely based on luck.