The headline itself is an example of a question that answers itself.
Another example would be "if you've saved up a lot of money, why don't you spend more?" Well because I saved it by not spending too much.
And in this case, "success" is working long hours, because of what these workers believe. Success is the appearance of working hard, and having put the effort in.
The article doesn't really address income/spending, though. Are they making excellent money because of working so hard? What do they do with it? If they spend most of it, they have to keep earning to sustain their lifestyle.
Of course, some people spend little, work hard, earn a lot, and perhaps never reach "enough", where they can work less, spend a bit more, and actually enjoy the fruit of their labor.