Actually LA is fairly conservative in its dress - refined Italian fabrics, subtle patterns, understated colors, beautiful cuts of clothes. Part of it is the soft light which rules out the dramatic primary colors that look so good in steely New York - and part of it is uncertainty about taboos and going overboard (for which see Joan Didion and Scott Fitzgerald).
Plus with the Oscars you have to compete with the red carpet as background, and who could paint on a red canvas - except perhaps for Matisse? That's why black does well, the tuxedoed men especially.
The effect of this upper east side group, who go back to Holly Go-lightly, is totally unimaginable in LA:
"Fashion is commerce but ..."http://video.nytimes...100000001350071
Altman tried it, more or less, with Pret-a-Porter.
But Sturges, who after all invented kiss-proof lipstick, would be good with the contradictions and reversals, such as the wrong watches worn.