It's even worse when the person who had the luck/timing in a previous success sets out to recreate that success and doesn't adjust to the changes that have occurred since. At least one such startup I've worked at the CEO had what we referred to as "Delusional Rich Guy Syndrome". Many of the investors he teamed up with also shared the same disease.

It's the idea that somehow, all the other people that failed lacked their special innate abilities so this time it will be different.

Also, consider that ability is distributed more or less on a bell curve. Effort... I don't know, but you can't work that much more than the average for that long, so bell-curveish, again. However, in modern society, rewards can be way, way outside the bell curve. Not that that's a bad thing, or illogical - a new invention that makes millions of people's lives better is worth a lot of money and should be rewarded - however, maybe it's one of the reasons that people are a bit suspicious of extreme wealth.

That's true, though I would guess that for the upper echelon success you need all: luck, timing, intelligence, competence, etc.

"Syndrome" just means this is a common pattern for successful people (independent of whether they are right or not about the role of external factors to their success).

For example, from the article about entrepreneurs and impostor syndrome (linked from the Wikipedia entry):

"Psychological research done in the early 1980s estimated that two out of five successful people consider themselves frauds".

http://www.inc.com/magazine/20060901/handson-leadership.html