It's not just what you wear but how you wear it Catman...
A lot of supermodels, superrich & creative types travel in first - they're not going to be wearing suits. On the other hand, someone who's just spent six months backpacking around the Himalayas & hasn't seen a bath in a while is not likely to be upgraded (except for me after my night on the floor at Heathrow).
Do you think that the airlines consider who their paying (ie full fare) customers might want to sit next to?