Even if you would only have passively invested funds, you'd still have the pricing mechanism. Each index fund has an individual portfolio distribution and diffe

Even if you would only have passively invested funds, you'd still have the pricing mechanism. Each index fund has an individual portfolio distribution and different rules of how to adjust it to market changes. Passive investing doesn't mean that there is no "active" part to it. Furthermore, a great number of stocks won't be part of any index fund, hence you'd still have active investors (humans and/or machines).