Do you really feel that pressure outside of a professional environment, or the MN S&B boards, Bani? Going braless isn't a massive taboo here, more standard among small breasts but it's not exclusive to them. I agree that arguments of necessary 'support' are without any evidence (exception, indeed, to sport bras during high impact activities).
I did look into the theory behind the bra intervention method (and its various guises) at some point. It was interesting to see that it mostly stems from a few prominent UK bra brands who are all pretty much educated by one specialist school/college who teaches this method for fabrication.
Personally, I'm convinced there is an economical motivation buried within it, if your customers are buying bras to wear extremely tightly at the start they're much more likely to be breaking the elastic than stretching it to get it to fit to a point of comfort. Add in normal wear and regular washing, and your customers will have stretched out those bras far quicker than they otherwise would, and since the difference between extremely tight and stretched out is far more noticeable it will incentivise an urgency for purchase whereas most of us wear out bras for an embarrassingly long time. High initial purchase price will mean they buy less but more often which is more sustainable for a specialist business model, I'd imagine. Also, I think even the smallest breast measurements start at a D cup at minimum within that method, putting a substantially larger majority of women in the premium large cup range tier. The advice I've seen on here about getting new bras every 6 months seems absurd to me, especially considering that these hard to find sizes come at high prices.
Like I've mentioned previously, I'm glad it works for people but it seems to be predominantly people who should have been buying the bigger cup sizes with the wider bands, etc. rather than buying within 'regular' sizes. I also can sort of guess how the mismatch in band sizing arose, inches aren't as exact as cm, the Euro brands have more scope IME so you're more likely to be one or two sizes off at most usually for the sake of comfort, and what's wrong with comfort anyway? I think I'm mostly annoyed with 'the right size' mantra, and constant news articles of 99% of women are wearing the wrong size bra which I'm pretty sure are circulated by bra manufacturers. I think the right size is simply the one that fits in a way you like, whatever that is, there's far too much variance between breasts (never mind the brands) for them all to have a standardised 'right size'. The only time you're not wearing the right size, in my book, is if you struggle to find any options in what you perceive to be your 'right size'.
I disagree with Mr. Bani though, taken as a group teenagers aren't exactly attractive. We tend to view children as especially beautiful (survival thing to make sure we take care of them even when they aren't ours) that's expressed in odd proportions when viewed objectively, predominantly in their face, large round eyes, long thick lashes, full cheeks, perfectly smooth skin, etc. Adolescence isn't all that linear so those proportions go all over the place until it all settles. Even then, most don't hit their stride until their twenties or later. Some are lucky and it all works in their favour and they stand out immensely but they tend to be a very small minority. I think the appeal in youth has always been more what they represent and most of us took for granted when we had it, their life still ahead of them, endless choices, freedom of responsibility, relatively unharmed by the worst life has to offer, etc. We make them out to be a lot more attractive than they are, IMO, but there is probably a gap between what teenagers consider attractive vs. the generations above them.
I find it an unhelpful obsession though, I remember my teens being dominated by this constant 'this is the best it's ever going to be, this is you in your prime' narrative. It's pretty depressing if it doesn't feel like that, but you're all convincing each other this is most desperately the case, and you're made to feel guilty for not being the best in the limited period of time that's apparently been exclusively earmarked for it.