Not familiar with "Fast Fashion".
"Fast" apparently refers to quickly discarding it. Not that you have to be quick to purchase it on Day One.
Definition of fast fashionan approach to the design, creation, and marketing of clothing fashions that emphasizes making fashion trends quickly and cheaply available to consumersThe result is a new and even faster kind of fast fashion, which encourages consumers to buy heaps of items, discard them after a few wears and then come back for another batch of new outfits.
It’s obvious you’re not familiar with fast fashion. You don’t understand the concept of a limited edition drop.