Just because you perceive a person to have everything they (or you in this case) could ever want, doesn't actually mean that they have anything they want or that they are any happier than you or I. Regardless of what anyone thinks of acting/filmmaking, it's still a job - it's still work. It's even a stranger and more time consuming work than the standard 9-5 office gig.
On top of that it sounds as though you're equating money and fame with happiness - do you really believe that? Does money really buy you happiness? Would you be any more happy in the long run if you had more money?
Money simply buys more stuff, or the ability to do more stuff. It can't substitute for missing fulfillment in one's life. People seem to have the notion that if someone is wealthy, famous, has a cool job or whatever else we wish we had, they are somehow immune to the same drudgery and daily things that drag us down, upset us or make us angry.
We all have our own problems, faults, weaknesses, strengths and desires that constitute what makes us happy, or not. Don't be so quick to assume that because someone has what you perceive would make you happy, that they too should be happy and fulfilled within their own lives.