No shit. Taleb would say: "those who can, do. those who can't teach others or write about others doing it". Just look at the financial press which is the last place you should look for market analysis.

Not really universal though: maybe some people who write about axe-murderers would be really good at axe-murdering, but for some reason they never tried. (At the opposite end of the spectrum you have professional sports and those who write about it)