I think the critical word is 'be'.
Perhaps the reasons are complex and psychological rather than financial and profit-motivated. Many people want to be something/somebody who is defined and realised by what they do. On top of that, there's an in-built prejudice against defining oneself solely by one's financial worth.
Many of us have been conditioned to expect that for more work / activity, we should receive more reward: even if its not financial, we get an emotional reward from the challenge and from the outcome. But also from the act of being active in seeking and finding something - the more active, the more extended the feeling of achievement.