I could have spent three years writing and reading and working on interesting projects, instead of enduring the sociocultural hell of high school.
That - right there- is exactly why this person and most others need to be in high school, so that you can learn how to deal with your peers once you're all past puberty and starting to sort yourselves by definitive skills, talents, and motivations while you still have enough pre-adult protections and guardians to let you make mistakes. Because learning the subtleties of adult interpersonal interactions is crucially important for success in work, romance, civic life, and adult friendships. Running away from all of that just because you are not mentally stimulated enough in math or art class is a pale excuse for not facing your social emotional deficits as a budding adult. Academic enrichment is MUCH easier to tack on than proper socialization from school.