No, that's not true. I have a Ph.D. in electrical engineering from Vanderbilt and an MBA from Emory university. I can't go to the high school 6 miles from my house and teach the freshman algebra course.
The funny thing is, even if I went back and got my teaching certificate, I couldn't teach the mathmatics course since my college degree isn't in mathematics as well (that's a math-specific issue).
electrical engineering and your business background arent math degrees. though a ton of sophisticated math is involved, they arent math degrees. if your major was math and you took that to a phd, you would be certifiable in math after taking about 8 teaching classes. my wife is a teacher, i know all about the certifications and degrees. simply put, though you are extremely educated and obviously very smart, you didnt major in math. why would i want an electrical engineer teaching 8th grade algebra? thats why the certification system has been pushed in place. to weed out all of those who arent supposed to be there, regardless of their background. the smartest people are usually the worst educators because they arent able to break down and chunk information for the variety of multisensory learners they will teach. they can teach themselves and thats it. thats why teachers need to be certified. its also a racket set up by the states to ensure consistent income from a source that will never disappear.