Why is Polo Ralph Lauren different from the other labels?

It's old world preppy. It's very clic compared to the brands you mentioned like ck, hugo, armani. They all go through phases dictated by the latest fashion.. you might buy something there which in a year will be old fashioned. At RL on the other hand you could pretty much buy things which will never go out of style. RL manages to be modern and the styles look just as good as these other brands, whilst retaining its signature clic touch.