This is called male privilege. Not being on the receiving end of sexism insulates you. You have the privilege to be blind to it, and to its effects. You don’t see it because you don’t have to.
That these young women had success doesn’t mean that they didn’t have obstacles in their paths, it means that they overcame the obstacles they encountered. It doesn’t mean that they didn’t have detractors, it means that they ignored or defied them. It doesn’t mean that they didn’t have people scoffing at their achievements, it means that they didn’t internalize those messages.
People have said “you’re not good enough” to every successful woman you can think of. Hillary Clinton just went through a year+ of people telling her that she wasn’t good enough, often for the most spurious of reasons. When she had a long, tiring day on the campaign trail and was being called everything but her name she cried, and the gender-based teardown went into hyperdrive. Justice Sotomayor just had Senators who can’t string together a truthful and coherent sentence saying that she just wasn’t good enough because she dared to view the world through Latina female eyes, not “normal” white male eyes like theirs. Sandra Day O’Connor, Ruth Bader Ginsberg, Diane Feinstein, Nancy Pelosi, Barbara Boxer, Carol Bartz, Meg Whitman, Carly Fiorina, Kathleen Sebelius, Janet “has no life” Napolitano, every single one can point to instances even after they were well proven to have exactly what it takes to do what they do and do it well where they were told that they weren’t good enough, for ridiculous reasons, many of which boiled down to having the wrong equipment between their legs.
Nitpick - there was no vice principal in the Grease movies.