Capablanca said `You must make your move without hesitation`. Which I take to mean, without fear. I have lost many games just from tensing up in an awesome winning position, and instead of continuing to make solid moves, deciding to sacrifice without reason just because I couldn't stand the pressure, lol. Usually against a higher rated player.
The real root of chess talent is character.
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He meant before you talk yourself out of playing good moves (I've done so) and he doesn't mean the first move that comes into your mind but rather your chosen candidate.
Getting nervous can cause bad moves, which is why one must be cool headed and calm.
Maybe you think you're stupid but don't really have a character or disposition conducive for a traditional classroom setting. I can imagine Tal with his tendencies to have a hard time just sitting there listening to someone talk, yet he was a bright guy. Dvoretsky says that many of our mistakes come from character flaws.
Well written OP
People are oftentimes surprised to discover that intelligence weakly correlates with innate chess strength, but what could really be behind chess talent? Surely such innate ability is symptomatic of something else? I believe that something else is character. Patience, cool headedness, and perhaps above all an instinct to look at things from the opponent's perspective (prophylactic thinking) contribute to chess talent. Capablanca's legendary talent is rooted not just in his intelligence, but his easy going nature and ability to keep calm, and thinking about his opponent's plans. Critically looking at one's own plans and a penchant for self-criticism also factor into chess talent, for one must be a skeptic at the board. If someone makes a sacrifice or is clearly following an attacking plan it's as if you're asking, "No, you show me an alien/bigfoot/whatever." Of course many sacrifices are indeed sound so the analogy may be weak but the point of approaching the position with skepticism and methodical doubt still stands.
Is this a fact? No, just my opinion.