[lend000]

> it contributes capital to companies that will succeed. How is this "No value to society"?

Because pumping up the market value of a "bad" company contributes negatively (not zero) to the economy. Any benefits that a future innovative company would reap from your capital are canceled out by the same benefits that their wasteful competitors reap for talent and secondary stock offerings (which can be spent on anything, potentially bidding up prices of raw materials, real estate, etc. for the "good" companies).

Is it a perfect 1:1 cancellation? Probably not, but it requires too much data for either of us to calculate it directly. But a fair assumption is that blindly investing in the entire stock market via a passive index, even if you are hugely wealthy, has negligible benefit to GDP, compared to active investing (assuming you are good at it).