Actually - external searches are often done for Chairman.
In Orstraylia Heidrick and Struggles and Egon Zehnder are regulars in that lucrative little gig.
A current Chair worth their salt will have a good idea of which director they mightpromote to sit at the head of the Boardroom table, but they'll also look outside the organisation as well with the assistance of a search firm.
It's quite a structured process.
Again - OW would have to prove she could run a P&L.
Marketing, Corp Affairs are overhead roles - you don't make any coin for the business.
The Board wants to see a proven track record that you can operationally run a large business, successfully drive change and make an acceptable profit. Put simply, you need to be a statesperson par excellence and know how to get large groups of people to do what you want.
She doesn't have that experience, and would need to spend a few years successfully running Jetstar or a part of the mainline business for example before she could put up her hand.
That's why the AFR have called her an emerging leader.
Cos she ain't there yet.