Why would it be "beyond the capabilities" of some hypothetical leader from the private sector? I have no doubt that there are people who are leaders in the private sector who would also have the capability of being good executives in the public sector.
Just as someone who is good at computer programing could also be an excellent musician and play in a professional band.
But you wouldn't assume that a person who was good a computer programming COULD play an instrument, or assume that a guy who plays football could also sell real estate.
There is nothing inherent in being the president of a small company that shows an ability to run a government.
Godfather's pizza was a subsidiary company with low sales figures. When he took over, it was only the 5th-largest pizza company, with sales of $325 million. WHen his group bought out the company 3 years later for $40 million, the sales figures were about $242 million. When he finally left the company a decade later, they were down to the 11th-ranked pizza company, with sales of $287 million.
Now, how does that record show any ability to run a country with a budget of trillions of dollars? It doesn't. Neither does his time as a lobbyist for the Restaurant industry (a position from which he attacked Clinton's health care law, not the concept of overhaul which he thanked Clinton for, but just because the specific proposal would hurt the restaurant industry).
And he was on the board of the fed for a while. But I hardly think that qualifies him to be President either.
He is certainly competent, and passionate, and a great speaker, and has many good conservative viewpoints. But his record in the private sector does not indicate the ability to be commander in chief of the armed forces, to evaluate legislation, to deal with co-equal branches of government which he can't order around, or how he will compromise with others to get what he thinks is important.
Just as one example, the President has to vet and choose thousands of people to fill important positions in the government. What record do we have of Cain having to do something like that? We know he thinks Romney would be a great President, and he loved Alan Greenspan -- should that make us confident that he's going to pick good people for his cabinet, or to run other federal agencies?
He brags about not having a traditional campaign; that unfortunately also means that he has a small campaign staff, so we can't even use THAT as some clue as to how he'd fulfill that part of the job.
Note that the media ignores all this. But they won't. Some fringe groups are already putting together the research. For example, expect the question -- if PIllsbury appointed Cain to turn the company around, and Cain did so well at turning the company around, why did Pillsbury then sell the company to Cain at a loss? Isn't the point of a turnaround to make a profit on the company?
Cain will have answers, hopefully. But if he doesn't, the media will have a field day, either after he is our nominee, or Romney will do this when Cain is the only conservative left in the race.
We better start asking the tough questions now.
Here’s my answer: all it takes to be a good president is common sense.
There’s no such thing as good “governing” as distinct from any other sort of complex decision-making.
“Now, how does that record show any ability to run a country with a budget of trillions of dollars?”
If your standard for this “trillion dollar ability” is accurate, then there’s no reason to believe you have the experience merely to ask the question.
That is to say, working with larger or smaller numbers requires a only difference in mathematical calculation, not in the nature of practical application. A president simply has more people working under them than a corporate CEO.
(And of course, our goal is to decrease the former number.)