Cool. They can retire and one of the thousands of other people who can (and want to) do their job can step in. If that starts causing problems, companies need to work on training programs for their leadership. It'd be an amazing side-effect if this pushed us toward it being more common to "rise through the ranks" and end up CEO. And if it caused us to start generating tens of people with a $100m net worth for every one one billionaire we'd have had otherwise.