I read the comment to be working hard is what brings satisfaction. Some people really enjoy hard work and aren't doing it just as a means to afford leisure.
The link is mostly about what happens when there is too little currency. Someone deciding to work 40 hours a week instead of 70 would, if anything, reduce the amount of currency in circulation because more wealthy people tend to have larger savings and a person working 70 hours a week is probably making more money than if they were working 40.