Hm. What about other things though, which are not the job, but still require effort/work? Like working on free software, working for a social project, being politically active, doing things of charity reasons ... Those don't require one to define oneself in terms of how far one has gotten in their career, but they actually add value to society. In many cases adding more value to society than the actual job. I think it's quite OK to define ones worth using such measures. We all live in a society. People should ask themselves more often how much they contributed to the well-being of society.
Volunteering tends to be an elite activity anyway. When people have to work multiple full-time jobs just to survive, it's just not very helpful or meaningful to ask whether they might find their inner fulfillment by helping out at the local animal shelter.
