Here's a question: Does someone whose main, perhaps sole, expertise is in the management of a company have the expertise needed to run a government?
There is a large group of people who have that expertise that say "of course", but where is the evidence?  And why exactly would business skills be the sole or primary skill set needed to run a government?
A government is not a business, it is a different entity.  Government should be run in a business-like manner in many aspects, including project management and financial management, BUT government is not business and many of the hallmarks of modern business practice, including focus on quarterly returns, profit as the primary metric of success, would be detrimental to good governance.
We have an object case unfolding to the south of us, where early returns indicate that being clueless about actual government function is not such a great thing.
So maybe Trump will end up blocking O'Leary.