One difference between professional traders and amateurs is that pros don't judge a trade by its outcome but by the idea and its execution. What makes something a good trade is if it is a good idea at the time based on the available information. But even the best idea may not work out and that's where risk management comes into play. Conversely, you can also make money on a bad trade, but it's still a bad trade. A professional trader's job is not to predict the future but to make good trades.
Taleb's idea may have been good at the time that simply did not work out. Of course, his statement tells you nothing about the concrete implementation of this idea which more often than not will make all the difference w.r.t. a trade's outcome. Maybe he even did actually make money from the idea. There's really nothing to suggest that he would have shorted in 2010 and just held the position since then.
Taleb's idea may have been good at the time that simply did not work out. Of course, his statement tells you nothing about the concrete implementation of this idea which more often than not will make all the difference w.r.t. a trade's outcome. Maybe he even did actually make money from the idea. There's really nothing to suggest that he would have shorted in 2010 and just held the position since then.