'Why the algorithm that promised to save Hollywood destroyed Relativity Media'

[David Peterson]

And how do you identify a trend change? By losing money following the old trend until you've identified the new trend.

Nope, not always, as there are many other ways. Such as often there are leading trends that precede another trend, so that one can be used to predict when the other one will change. But anyway, often simply being the first to spot (thus a key use of powerful tools which can do this) that a trend has changed is a sufficient edge on the rest of the competition, if they're just continuing on oblivious to the change that has already happend.