Though in this case, I think you may be neglecting one thing. As the article mentions towards the end, humans are creatures of comparison. Someone earning around 60K in America can see that they are better off materially than most of the people in their city and if they pay any attention at all to the world they will know they are vastly better off than the majority of the world. At that point they are hardly wealthy, but better off than most.
Yep, I was going to post exactly this. You can be making 200k/year, but if you're a trader and your peers are pulling 400-600k, you're very likely to be unhappy with your predicament.
Humans are competitive. If you have the best mud hut of everyone you know and know of, it seems likely that you'll be just as happy as that top trader, with regards to wealth.
Though in this case, I think you may be neglecting one thing. As the article mentions towards the end, humans are creatures of comparison. Someone earning around 60K in America can see that they are better off materially than most of the people in their city and if they pay any attention at all to the world they will know they are vastly better off than the majority of the world. At that point they are hardly wealthy, but better off than most.