[ookdatnog]

There seem to be quite a lot of people who really need to believe that luck plays at best a minor role in (their) success for their sense of identity to remain intact, and who get incredibly defensive when this notion is challenged.

I guess in daily life it's a useful self-delusion. A mostly harmless belief that gets them through the day while being obviously false: if you're born in the middle class in a developed economy in the modern day, you're likely to be vastly more lucky than, say, 99% of all people who have ever existed so far.