The industry takes vast amounts of natural resources and uses them to make money for a few people, make a few people feel a bit better about themselves and make a lot of people feel insecure. It is a very harmful development of the modern age and is bad bad bad
The fashion industry has put forward an idealized view of women, that is impossible to attain. Especially for impressionable people, this imagery can create a feeling of inadequacy, and even lead to eating disorders. As a society, we should work to stop accepting this skewed ideal, and support fashion labels that hire average-shaped women to model their clothing. The fashion industry won't change unless we change what we're willing to accept.
And that's bad for society. In a perfect world, people would be rational and would realize "well, why should I buy this purse / coat / pair of shoes / you name it just because someone is advertising it, it's dumb and I won't do it". However, we are way less rational than that. Teens have long needed peer approval, so if the cool guys and girls are wearing something, they would buy it right away: and nowadays even people in their forties behave like teens, the same insecurity, the same dumb need to fit in. The purpose of clothing is weather protection, and a no-brand t-shirt which cost 2 dollars to produce and sells for $5 is just as good for that as a big brand tee which also cost 2 bucks to produce, but sells for 30 and, to add insult to injury, carries its own advertising, one the tee owner paid for instead of being paid for. So even if society gladly embraces it, fashion is bad for all of us.
People need to learn to get over their "insecurities", and not blame the fashion industry for it. Every soul has a right to express itself. Fashion is a form of self expression and should definitely not be compressed.
Fashion is not about money. You can spend 10 dollars on your outfit and still be considered fashionable. It's stereotypical to think of fashion as restricted to only expensive fashion labels.
The fashion industry allows others to express themselves in a way that excites them. It is not harmful when people are enjoying themselves and a culture is evolving from it. The fashion industry can be very beneficial in this day and age. This is why it is not harmful to our society.