Jerry Jones is a shitty GM and an egotistical douche, but he is one hell of a business man no matter how you look at it.
There's really no quantifiable guideline to tell whether Jones is a good business man or not. He made his money in oil and gas when luck, not skill, was the determining factor of success or bankruptcy.
I believe any success the Cowboys have had under Jones rule is directly related to only one person....Jimmy Johnson. The facts back that up.
How many Championships have they won since Johnson left? One and the roster was made up of 50 players selected by Johnson!