Feel free to disagree with this, but then Senator Obama also had little executive experience, so I don't think that's a card that Democrats should play against Ben Carson. I'm more worried about his lunatic beliefs.
Obama was a senator.
Which means he was in the legislative branch, not the executive. As I recall, before Obama/Biden won in 2008, the last Senator-Senator ticket to win was Kennedy-Johnson. Typically it was Governors or Vice-Presidents who won Presidential elections.
Honestly I don't understand why the role of governor is considered a much better preparation for president than Senator.
Because Governor is an executive branch position and Senator is not.
By which standard the best qualification would be some Secretary role.
This is something unique to the US - the belief that people with no Federal experience are better qualified for that job for that reason.
Not some Secretary role. Governor is the position most analogous to President without actually being President--chief executive of a government.
Except the things you deal with are radically dissimilar. What's a governor's day-to-day job? Law enforcement issues, public health, transport. The president has to maintain national security and negotiate with other countries. Governors simply have no frame of reference for that, unlike, say, Secretary of State, or a Congressperson.
Well, if we're looking at it like that, the C.E.O. of a very large successful company would be pretty similar. Budget constraints, administering a massive entity, dealing with "the other side". And they are usually beholden to shareholders.
CEOs are very rarely beholden to anyone. Shareholder rights are very weak in the US.
Being a CEO, again, is radically different to being president. There is no separation of powers, there are no treaties to negotiate, no laws to write or Senators to negotiate with. And the objectives are radically different - you're not there to do the general good, you're there to make a private profit. Other people are subordinates, not citizens.
By far the most successful presidents are Senators (Johnson, Kennedy, Lincoln, Obama, Truman) or Secretaries of something or other (Bush the Greater, FDR, though FDR was also a governor of New York for one term). The only actual CEO to ever become president was Bush 43 and we all know how he turned out.
Probably the best qualification of all is the Vice-Presidency.