Plus everything op said about capitalism and market.
I strongly disagree. It's a matter of surrounding yourself with capable people and there's a huge factor of financial inertia. I guarantee you most HN-ers could run Google or Apple for 5 years without causing their value to plummet.
I still don't necessarily disagree, but you left out the second part of my sentence which is rather significant:
"and will be acceptable candidates in the eyes of the board/shareholders."
That doesn't mean they are going to be remotely acceptable as a candidate in the eyes of the board + shareholders. Nobody is going to stick their neck out for Random HN User #587942. They are going to pick somebody with a positive track record of leading big companies.
This isn't ideal! I'm not defending it. I'm just saying why it happens. It's the C-suite equivalent of "nobody ever got fired for buying IBM."
The world is not overflowing with people who can even theoretically lead a $77bn company and will be acceptable candidates in the eyes of the board/shareholders. So you will need to pay accordingly if you want one.
It's like wondering why pro sports teams give megabucks guaranteed contracts to superstars. There aren't a lot of them and there is a lot of money at stake when it comes to running a successful pro sports team. So they cost a lot of money to acquire.
I am by no means defending this. Whether or not one thinks there are better alternatives to capitalism, it's hard to deny that capitalism produces some pretty crap outcomes.