wooo wooo someone call the fashion police!!!
I agree with you that logo jerseys when you're not sponsored are kinda stupid, and bibs look awful, and even worse if you've got a gut, but no one appointed me the fashion police, so I figger what people choose to wear when they ride their bike, and what kind of bike they chose to ride is no business of mine, and certainly has no bearing in my mind on wether they are a real fixed rider or not.
You'll have plenty from "urban culture" who just ride to the coffe shop, and plenty from road culture who buy all the kit, and don't really ride. You'll also have riders from all niches who are serious about riding, and whatever that means to them is a personal thing.
I couldn't begin to guess how many fixed riders are out there, but when you add in arbitrary qualifications like fashion choices, and populaion density, it would be impossible.