Over at GNXP, I wrote a brief guide to cleaning up your nerdy appearance, emphasizing professionalism and making the place look nice, more than looking hot to get girls (though that's a good reason too). One thing I should've mentioned, but which was beside the main point there, is that it's a mistake to believe that putting more effort into our dress is bad because it might stoke class tensions, so why don't we all dress really down and be happy in our equality.
On the contrary, the downward spiral of casualness only increases the variance -- or as it's fashionable to say, it exacerbates the gap between the rich and poor. When even those at the bottom rungs of the white collar ladder dress more formally, and when (for example) waiters and waitresses are provided with stunning formal uniforms by their employers, both public and even private life has a much more polished look. Differences remain, but the contrast between a low-level white collar guy and a CEO is not night-and-day.
Once the more formal standards are abandoned, the very richest retain their impeccable attire -- Wall St. bankers will never adopt cargo shorts and polo shirts for work -- while everyone else tumbles into slobdom. The middle falls out, and now the differences between a CEO and an office worker look like something out of a muckraking cartoon from the Robber Baron era. Except, as Donald from 2blowhards pointed out, it is voluntary nowadays to look unkempt. As such, it could easily change if the will were there.
And when people are not in their "work-gear," these differences become downright embarrassing. The discrepancy between the suit of a low-level white collar worker and that of a CEO is noticeable, but it takes some investigation, and many naive people could be forgiven if they didn't see much of a contrast in the first place. However, look at the Wall St. banker in his t-shirt and jeans next to an office assistant in his t-shirt and jeans. Unlike a jacket and tie, the t-shirt and jeans look is pretty difficult to make look impressive. You could easily be mistaken for an unemployed or homeless person, but not so with a jacket and tie.
Sporty looks can be done right -- for a hefty price. While a jacket and tie from a low-level department store at least stands a fighting chance as a replacement for a $2000 suit, t-shirt and jeans from the same store would be hopeless to replace the $250 jeans and $150 t-shirt that would be required to pull off the relaxed look with some dignity and style. It's bad enough that a more casual approach results in less impressive items, but sub-CEO people are not merely wearing sporty designer sweaters and sleek jeans. The combination of these two effects really hollows out a large chunk of the public who would otherwise look pretty good.
Since the result is to push middle-class people to compete in an area where they are absolutely doomed -- casual sportswear -- let's ask Lenin's famous "who? whom?" question. Have the countercultural class warriors created the "less formal" trend in order to brutalize the appearance and self-confidence of the working and middle classes, exaggerating the most easily visible differences between them and the upper classes, all to fan the flames of inter-class hatred? "Guh, look at that pig in his yuppie suit!" etc., from a person who not long ago might have worn a jacket and tie himself.
Given that most of those who champion this credo harbor a more intense hatred of those above than a love of those below, this interpretation may not be as crazy as it sounds. Of course, I haven't read any of the popular (let alone, er, "scholarly") books on this subject, so this could have already been suggested, debated, and defeated. It's just hard to see who else benefits -- well, the upper classes themselves, but they can't control how those below them dress... without a mole to do their work from the inside. Those would be the celebrities -- from sub-elite backgrounds but who connote "high class" in the minds of the populace, and who enjoy dragging standards down, often into the gutter. But celebrities are for another time.