But even that isn't necessarily true. I know of several managers who didn't work hard to get there. Theh were just in the right place at the right time, or in some cases the right gender.
We can abstract this a little. You don't have to work hard. You just have to appear useful to the people in power.
I worked hard in the past. I'm not working hard now - I'm really slacking now that I know I'm screwed. I'm still getting paid the same.
My reading of the Essay was that hard work was necessary for great success not sufficient, which would be a very different claim.