I do not feel that fashion, style and trends are the most important things to being successful in life. Many individuals have expensive gear (Beats headphones, most expensive smartphones and most expensive apparel) but they belong to the middle class society. Having a high-paying job by having a degree (whether it be undergraduate or graduate degree) are two of the most important things to being successful. Being successful means being consistent in your work ethic and your routine, as well as being in a stable environment with very few volatile moments to tip you off the scale. A man can dress modestly but be a millionaire, and at the same time a well-dressed man can disguise himself as being rich; it does not translate to success, but rather, it could translate as being a facade for the person's reality in life.
No, what's in your brain counts for more than what's on your back. It's not that people who care about things like fashion and style are not people of substance, it's the idea that how you present yourself physically is more important than what you have to say. Looking good and put together makes a impression, but that's really the lead-up to the main act: the thoughts and ideas that package contains.