And I do feel sometimes like Stacy and Clinton act like everyone should be spending lots of time paying attention to fashion trends and the like - and mostly, I just don't care that much. I just try to dress sensibly and comfortably for the occasion, personally (although I do wear makeup).
Ultimately, people who are completely unaware of fashion trends are the most likely to wear clothing that looks dated. It's really easy to get used to wearing a particular type of clothing that you see as "classic," and not realize that everyone around you sees it as trendy...from 10 years ago. If you don't pay at least some attention to fashion trends, it's incredibly hard to know what's a trend and what's just a basic, classic wardrobe item.
WNTW really does focus most on those basic, classic wardrobe items, too. Most of the participants end up with things like really great basic pants that will last for years, look flattering and fashionable for years, and thus justify their probably steeper-than-usual price tag. Whether the person who owns the pants wants to pair them with trendy accessories/tops or more classic wardrobe pieces is up to them, but you won't ever be able to identify the non-trendy pants unless you know what trendy looks like.