One thing that influences - probably partly unconsciously - our sense of 'what suits us' and what looks good, or pulled together, on other people, is what's generally in fashion. Not in the sense of 'this season's colours' but in the sense of large, overarching trends. So if you look at photos from the sixties, most women had nude-ish lips and exaggerated eyes, in the seventies most women had something glossy or shiny about their make-up, in the eighties face-shaping was in, and so on.
So at the moment, what's in is very heavy eye make-up and nude lips. I keep seeing a L'Oreal ad which parades that look to the nth. There's not so much bright lipstick around because it's not very fashionable, and so we are not seeing it as very attractive - or, at least, we are not seeing it as very attractive on most people. When I was out yesterday I saw two people with bright lips, and one of them was me, in the mirror.
I happened to look at some photos of Marilyn Monroe earlier, and although she has low-contrast goldeny-blonde colouring (was a natural mouse colour with brown eyes and yellow-toned skin) she wore red lipstick and looked amazing. But she did her own version of a make-up look that was in during the years of her fame.
I guess what I'm saying is that if everyone was wearing bright lips then we'd all think it suited us more.