I would divide the old icons into stars and artists. The stars, such as McQueen and Newman (and, to my mind, Peter O’Toole and Cary Grant), were about physical energy and sexual presence. The clothes that they wore were important, but only because they displayed inner illumination to best effect. McQueen’s clothes, with a few exceptions — those suits in The Thomas Crown Affair, for example — consisted of simple and close-fitting sportswear. Sweaters and turtlenecks, snug T-shirts and white tennis shoes. But he turned these basic American things into symbols of an assertive, competent, striving masculinity.
The artists, from Miles Davis to Samuel Beckett — Jimi Hendrix and David Bowie go here too, I think — were all creators in the 20th-century mode. They were defined in large part by the rejection of classical or bourgeois conceptions of aesthetic or intellectual achievement in favour of greater spontaneity and authenticity. They were iconoclasts before they were icons. Their clothes are in one sense irrelevant, because it is the work that matters. But they were also absolutely relevant, because the work was not just changing music or literature but the whole way we approach life, right down to what we wear.
My guess is that two factors killed the style icons. First is a social change that has been much in the news in the past year, but has been brewing for much longer than that: a change in the ideal of masculinity. The political or professional destruction of sexual pests and predators, and the rewriting of the rules of sexual engagement, speak to a rethink of male sexual attractiveness — which is to say, male sexual power. I will not add more ink to the oceans that have been spilled on this, except to note the obvious: putting a male movie star on a pedestal has become a very tricky business.