I'll use myself as a proof by counterexample. When I was buying my t-shirts from places I actually wanted to support, like ThinkGeek, or buying solid colored t-shirts with no logos, I found that the poor fit of the t-shirts was making me look bad and feel uncomfortable.
Eventually I was talked into going "shopping" by a couple of female friends (actually, I talked them into being my guide), and found that the only t-shirts I could find that made me look and feel good, with a wide range of prices, also happened to have well-designed corporate logos on them.
So, until it becomes technically possible and socially acceptable to have custom-tailored t-shirts that fit perfectly, have the right fabric, pattern, and seam/collar/hem, and are emblazoned with my family crest or personal corporate logo, I will continue to buy whatever looks and fits the best within my price range.
ThinkGeek apparently uses Gildan shirts, which are cheap, baggy shirts made out of thick cotton; you were probably buying shirts of similar quality when you bought plain shirts.
Since it seems you're spending more on shirts now, you're probably getting a better quality product. Plenty of stores from Target to Gap to American Apparel and so on have better-fitting shirts made out of lighter-weight material with no visible logos, likewise in a range of prices.
Nike Air Pegasus 2 are the best running shoes I've ever had for training, I went through a gait and foot impact test at a sport science clinic to match shoes to my running style. Their combat compression kit is also some of the best you can buy in terms of lasting the year even when used every day.
Now if you meant those ridiculous Airs with the spring shocks in them then yes, but brands that endure aren't built on nothing.
While I do agree with the side you are arguing for, last winter I bought a pair of brown Lacoste shoes that had wool inside them. I sought out the specific pair of shoes because they didn't have a single logo except in the rubber of the sole and I didn't want to be /that/ guy.
