It's not necessarily as arbitrary as you're making it out. For businesses, the cost of failure is low and the potential upside is enormous. As a result, risk-seeking behavior makes sense, and people generally respect that. For humans, the cost of failure is very high, and the upside is only the productivity of one 2 meter bag of flesh with a brain inside. Taking existential risks as a human is foolish for reasons that do not apply to businesses.