It doesn't seem fair. But I guess demand for ceo's is high and quality ceo's are scarce.
On the other hand - it might be totally fair to be prosecuted for doing this... :)
As I said, most CEOs nowadays seem to behave like mob "cleaners". You want them to come in, do the dirty work that needs doing, and then leave. You don't want them necessarily going somewhere else after leaving you. So you pay them a lot, because you want them to live quiet lives afterward.
People at the top of the corporate and political ladders are excellent at one thing - bullshitting. Their job is the same difficulty as countless jobs which pay a tiny fraction of their salary. They're just good enough liars to convince everyone otherwise.
Anyone can hit rocks in a mine. It might be hard and stressful work, but anyone can do it.
Not anyone can make decisions and lead an entire group of people.
Leading is a skill just like mining or programming are skills - they can all be learned. Given the recent evidence of life-long brain plasticity, it's reasonable to assert that this is more a problem of nurture than nature.
In short, we train relatively few people to lead, hence the low supply.