Some of them are surely happy and successful. I'd like to think (no citation whatsoever), that a nontrivial portion of them have the mindset of "I'm currently b

Some of them are surely happy and successful. I'd like to think (no citation whatsoever), that a nontrivial portion of them have the mindset of "I'm currently building this empire and then I will reap the benefits of this vast wealth". They are not happy per se in the moment, but have some future vision of happiness away from the grind of being "successful". At some point, they realize that they don't have that much time left to actually enjoy life outside of amassing money/possessions, so they get obsessed with extending their life.