I disagree. Luxury houses absolutely have to rely on the perception they're prestigious to stay profitable and most are actively trying to play into that in their campaigns. In many cases, there's a huge disconnect between quality and price-point and desirability. The infamous $5,000+ Chanel t-shirt, for example exists only for that reason. Defective/sloppily constructed $8,000 handbags also from Chanel indicate that some Luxury houses maintain their status and stay in the black not through consistent quality and honest value but because they're able to sell the image and bank on perception. The couture at this point often feels like nothing more than a front to be able to sell accessories and fragrances. So-called Luxury houses are in a mad rush to be seen on the influencer set because they want to maintain the perception among the public that the wealthiest among us favor their brand. It's fun when those brands take creative risks and go in a different direction in their campaigns, but by and large they're actively trying to play into the perception and present their brand as synonymous with a lifestyle of luxury.
Zara, unlike most of its affordable peers, from an advertising standpoint, is competing in the same arena as the Luxe brands. They're hiring the best photographers, the best models, the best makeup artists, stylists, etc. And it's not just one aesthetic. Their S/S and F/W campaigns this year are dramatically different, yet both are phenomenal and put most others to shame. Even someone completely unfamiliar with various brands, when presented with ad campaigns, could likely easily distinguish which is more of a luxury brand based on the aesthetics. However I would be willing to bet they would mistakenly be putting a brand like Zara at or above the level of brands 10x/20x/etc. more expensive if they were looking at the S/S and F/W campaigns from this year. As you say, Zara has more cachet and prestige than other commercial brands, and surely the strength of their advertising is a part of that. In other words, they’re producing fairly ordinary, affordable, mass-market clothes but producing campaigns that sell them as more than that. The sequin top Sasha is wearing is under $100 and not really anything special but to my unprofessional eye if I saw the ad and someone told me it was Chanel and several thousand dollars, I’d believe it because Zara is playing the game better. They're exposing luxury brands by so easily replicating the kind of image those brands fight to maintain. And most of the other mass-market brands aren't even part of the conversation.