In a fast changing world, organizations need to be able to continually adapt to new conditions, new information and developments on the global stage. You need your senior staff to have widely applicable skills to be able to change as their roles change. Having a very specific experience base might be less important than having the skills to learn the job, the motivation to improve the context, the creativity to shape it to maximise their assets, the contacts with the subject matter experts, and the ability to work with others to get the job done well.
Need a new senior staff member? Advertise for a Julie Andrews. (After all, wouldn’t you like to work with someone who believes that, “In ev’ry job that must be done there is an element of fun. You find the fun and snap! The job’s a game…”)