Why do mainstream institutional traders always tend to price in "the best-case scenario"?

Modern financial models are based on normal distribution. For catastrophic tail risks like high-intensity warfare, COVID-19, and global supply chain disruptions, their probabilities are extremely low in the model, and once they occur, all assets suffer devastating losses.

For the vast majority of institutional traders, "betting on doomsday" is an extremely poor career move: if doomsday doesn't come, you miss out on a bull market or major rally due to hedging and face accountability or termination; if doomsday does come, all assets and everyone's positions decline together, making it appear you didn't make any major mistakes, and often there's a violent rebound after the decline.

Therefore, markets naturally tend to price in "the best-case scenario."