I don't see a case they describe where luck as a factor has been isolated.
As such luck really cannot be isolated as a factor. Instead tho, people who claim to be lucky can easily be isolated. They can be studied for what makes them "lucky". In this case it seems to be at least somewhat correlated with openness to unexpected outcomes.
If you have any more to say, or can recommend any related resources - books, articles, or so on - that would be massively appreciated. But even if this is it, all I can say is - wow. And thanks. The gears are turning in my head, as you've cleared up something for me that I could never quite get down. Thank you, this was huge.
The other case, which is what I thought the article was about, is more of an "opportunity" type of luck. For example, if you happened to find a £10 note while walking home. That would be called "lucky" but it is not simply the result of chance: it is the result of you being more observant than everyone who didn't notice the money before you. And in that sense, people can easily be "luckier" than others, as the article describes.