I think anybody can write Haskell and anybody can play Zelda or similar characters in fighting games.

What the skill-cap / skill-floor thing is about, is how often do people bother. When the base level of skill required to play at all -- not necessarily play well -- is really high, often those characters don't get used as much. People find a character that demands less up front investment and play that character instead. It's not about ability, it's about time.