[ItsMonkk]

The trading industry is separate from the investing industry.

The investing industry is positive sum - but you must hold for the long-run, or only make decisions if new information is discovered to be an investor. Vanguard and other passive firms are a part of the investing industry.

As the GP says, the trading industry is zero-sum.

[mhluongo]

Not a fan of over-financialization, but... if trading is propagating market signals to people who otherwise wouldn't have them, it should have some positive externalities?