Most people who buy expensive clothing are actually doing it as a hobby, esp those that are being talked about in the article - people who are heavily invested in influences and celebrity culture, they find luxury to be fun and it allows them to hang out in circles of people with similar interests. So it does fulfill functions: aesthetic, social, entertainment etc.
How do we know that you aren't signaling you want that brand? You are just some dude in a Ford, who for all we know is signaling you want a Ford over a Chevy
Funny enough, it is a Ford, though I’ve also owned Chevys in the past.
You don't provide enough details here, but there's a good chance you aren't talking about the feature differences between a 1986 Toyota Tercel and a 2019 Camry. You are probably talking about the difference between your 40,000 or 50,000 (or more) dollar car and a typical 30,000 dollar car. If that's the case, it's probably worth pointing out while you criticize T-Shirt buyers, that you got horribly rooked. Rooked bad. Like, you're just a fat whale to the auto industry.
If I can find clothing that functions just as well as logo'd versions, but for less money, then that makes sense.
With cars, gaming consoles, etc., there's a valid reason to want to spend more money if you're looking for function. PlayStation has games that you can't find on other consoles, or maybe you just like the controller better.
The car I drive is more expensive than I need, but I didn't spend the money to signal anything to anyone. I bought it because it has features the alternative doesn't.
If those expensive sneakers do their job better, then great. But if you're dropping $500 on a limited edition, just for the design, then it's a different calculation. (I am NOT saying it's stupid to do this, just differentiating it from buying features vs. design)