Theres truth to the OPs statement. Some online sources say gates attended Montessori for elementary but it's not conclusive. Brin and page for sure attended Montessori. Bezos as well. I went to a Montessori until 5th grade and honestly didnt think it was anything special. Probably because they mixed a lot of traditional school elements in as well.
wikipedia said he went to a regular private school then went to Harvard which sounds pretty conventional. Yeah he didn't finish, but worry about that later.