At one point this would make index fund investing as a whole significantly less profitable. With all the horror stories we've seen unfold in the last five years, you could begin to suspect that boards actively and knowingly execute this strategy. You can only hope that a money manager would be smart enough to avoid the SoftBanks, Ubers and WeWorks. But I don't know that's a given. Shorting them out of your portfolio isn't an obvious strategy either, due to borrow costs and so on.
Anyone given a significant amount of thought to this?