Why charts fail?

"There are several reasons why individuals who solely rely on charts to make investment decisions may fall short of achieving adequate investment returns. First, they tend to purchase shares of companies after the shares have risen substantially—succumbing to the buy-high, sell-higher mentality. All else equal, this makes the purchase more risky. Furthermore, the buy and sell “signal” becomes less useful, as more individuals watch for these same market cues. The decision actually creates the opposite effect for the investor, as every buy signal actually generates selling. Those who are trying to gauge the technical analyst community understand that when such stock prices are up on technical signals, they are up artificially. Comparatively, fundamental analysis relies on original, proprietary work, and not groupthink."

Why charts fail?