There's really no reason to think that something that happened a single time in over 200 years is likely to happen a second time
Ehhhh... I mean Hoover was a businessman who never held elected office or served in the military, so he basically counts.
Willkie was nominated without having ever held elected office. He was a junior officer for 2 years during WWI and left the army when the war ended, so nothing like Grant/Ike/Washington, etc. on that front.
Lincoln had only ever been elected to the state legislature.
Lincoln served a term in Congress
Cabinet experience is political experience.
Being involved in the economy as a businessman or executive is extremely different from politics as practiced at the top level. Business owners can fire anyone incompetent or working at cross-purposes. Presidents can't. There were plenty of Democratic elected officials whom Donald Trump held in contempt, and so it is with many Republican pols that President Biden faces. In some countries someone like Matt Gaetz or Marjorie Taylor-Greene would have suspicious deaths.
Government cannot operate like a business. If a part of the government can be run like a business than maybe we have good cause to question why it is not part of the public sector. Natural monopolies, maybe? Government owning the productive sectors of the economy is Marxist socialism. We cannot run the judiciary, the police, or the armed forces for profit.
