Nothing lasts forever, including universal "truths". However, reality is stranger than fiction. When we lose, we won't necessarily lose to who we feared we would lose to. We might lose to some completely unpredicted for or foible.
John Bogle offered the first index fund for the every day investor in 1976. His research showed that it's difficult for a fund manager to beat the market, especially over the long term, even more so for investors having to overcome high fees, and it's almost impossible to guess which ones may do so beforehand.
One is best shot is to own the entire market and pay as little in fees as possible...the epitome of wisdom and simplicity.
Or maybe we will say it doesn't count as a failure if the entire market collapses. After all, our rival is active management so if both are failing, one would argue is passive index fund really a worse bet?
However, that isn't the whole point. After all, the question isn't whether to do active stock picking or passive but the question is to ask whether to do stock investing at all.