Scott Walker didn't build a company or have a real profession like Gates or Jobs. I have serious reservations about any politician who doesn't have an actual profession.
What? He pursued a marketing degree while working part time at IBM in a sales position. IBM later offered him a full time marketing job. He then dropped out of college because this was the job he wanted when he graduated college anyway. He then went on to fundraising for the Red Cross on the basis of this experience.
Walker is pretty awful and a bad candidate too, but this "issue" is a complete non-starter.