"Clothes make the man. Naked people have little or no influence on society" - Mark Twain.
Poorly dressed people fall somewhere in between. - my thoughts.
Really? In this day and age, all kinds of poorly dressed people have dramatic impacts on society. Musicians, actors, CEOs: Steve Jobs in jeans and a turtle neck had profound impact on society.
I think in the information age, the marketplace of ideas serves to reduce that quote quite a bit.
I'm a self proclaimed slob. I wear cargo shorts and polos to work, and until recently shaved every 4-5 days. I am highly regarded nationally in my field and within my company because I am creative thinker within my areas of specialty. And I work in a conservative field where most people do wear business formal clothing more often than many other fields.
I only dress up for conference presentations at the national level. The second the presentation is over, the tie comes off and the top button is undone, and the other days of the conferences are back to polo shirts and dockers. I also wear plain black new balance sneakers (designed for the USPS) with my suits, as I have not found a shoe yet that competes with the comfort level. People just think I'm quirky. But I have influence.