The community college option is available to anyone who’s willing to spend a couple evenings a week taking classes, so I don’t think it’s really that out of reach. Most countries don’t offer their high school students any opportunity to study material that advanced.

Your first 3 options are mostly “be born to the right parents”. So I couldn’t tell if your remark of “it’s more possible than you’d think!” Was serious or not.

Hell I went to a really selective school. But even then, within that the top students, whom I was not one, got to do some extra stuff that would have greatly interested me and I would have been able to do. But my grades in humanities weren’t good enough to be one of the best.

Community college course options often won't include quantum mechanics.