I'm in the top 30th percentile for household income in the United States. I recently had a performance review, was qualified "fully successful," and when I specifically asked my supervisor if I was doing anything wrong, he reassured me that there was not a thing I could change to do better. I receive regular monetary bonuses and praise, and was rewarded with a certificate of achievement just two days ago.

All of this despite the fact that I perform real, skilled work approximately one or two hours per week, and spend the rest of my time surfing the web, in plain view of everyone walking down the hallway, not even bothering to alt-tab when my supervisor comes into my cube to chat with me. (ETA: personally, I consider my work ethic to be atrocious, and if I were my supervisor, I would not tolerate what I have just described.)

I take the money provided and I spend it on various frivolous pursuits, and donate to SIAI. I'm not sure about long-term promotion potential, considering my lack of actual work, but it seems fairly rational in some sense that I take from the irrational and put in only what effort is required to achieve my goals, thus maximizing output/input (productivity).

The emotional impact of not making a difference is distressing, I agree, but that's a different, rather involved, topic.