It just won't happen, because there's a negative feedback loop against it, leading to a kind of homeostasis.
> At some point, no one is left to figure out which cookies are tasty vs meh, so the price of all cookies converge to a single price.
Five minutes later someone says: "Holy shit, I can make a ton of money by buying loads of cookies, sorting them, and re-selling them -- except with the definitely-tasty ones at a higher price."
I'm thinking specifically of attempts to artificially inflate crypto coin valuations for members, then quickly sell off before anyone catches on. Should be, I would think, impossible to do that across a large area of the market, but if everyone is investing in index funds, it might be, I would guess.
Nonetheless, for my situation, index funds are the best rational solution. That or hiding all my money under my mattress.
Except that there’s a lot of money to be made by figuring out which cookies are winners, and buying them cheaply to sell to the passive investors.
All the passive investors want is for their cookies (and new-cookie acquisitions) to be properly priced. No matter what, they have an average distribution of cookie-quality in their holdings.
The passive investors are not buying cookies at any price other than the market price. Whatever the clever-cookie-buyer is paying for cookies, they're paying the same. If a clever-cookie-buyer buys low, takes out an ad in Cookie Magazine, and sells high to a bunch of tasty-cookie aficionados, the passive investors win, too. If a too-clever-cookie buyer buys low and discovers that the apparently-tasty cookies have spoiled, the passive investors lose a little, too.
It is hard to bilk a passive investor. The first people to really figure out how will accumulate a lot of money (and ire).
> All the passive investors want is for their cookies (and new-cookie acquisitions) to be properly priced.
No, they want the cookies they purchase to be under-priced, and consumed once their price has gone up. The cookie analogy fails here, but passive investors are exclusively seeking return, not an efficient market.
> No matter what, they have an average distribution of cookie-quality in their holdings.
That's not how passive investing works. The classic model is investment in an index -- say the FTSE 100 -- which attempts instead to maximize the quality of holdings, not the most accurately priced.
> It is hard to bilk a passive investor
Yes, but that doesn't mean it's hard to make money off one.
Jack Bogle's view was that if the market is 50%+ passive indexed that would be bad news.
Some folks argue that the number is even more extreme, that passive indexing generally increases efficiency, and that as long as there are even a handful of active investors, the market will still be efficient: http://www.philosophicaleconomics.com/2016/05/passive/
The same author had another thought-provoking argument that the popularity of indexing has probably driven up stock valuations: http://www.philosophicaleconomics.com/2017/04/diversificatio...
According to this source, it already is [0]. HN discussion at the time [1].
[0]: https://qz.com/1623418/index-funds-now-account-for-half-the-...
In both cases the actual buyer is an intermediary, who is managing many people's money. Those people don't even know or care what is being invested in. If for some reason many of them decide to disinvest around the same time (say a recession) they may be hurting themselves due to the asymmetrical nature of the action.
At that point, an active investor can say that any losses by holding the stock an additional month would be eclipsed by selling immediately. A passive investment does not have that ability.