Why say that "luckiness doesn't really exist"? I expected you to say something like, luckiness is just the term that people have always used as a catch-all to s

Why say that "luckiness doesn't really exist"? I expected you to say something like, luckiness is just the term that people have always used as a catch-all to sum up all the things that matter, but they lack the ability to describe in any further detail.