What you say sounds wrongish... In a fast fashion shop you can try on ten things this week and ten _other_ things next week, and rate of change makes online ordering look slow.
1) Prototype to street was way more than 3 weeks. More like 3 months (still faster than most fashion which makes buys 6 months ahead). Zara is the main large retailer that is actually about 1 month from concept to store.
2) The quality of their men's wear was pretty good for the price.
3) They worked their corporate employees to the bone and paid them 60-70% as much as other retailers for the same job. Girlfriend ended up doubling her pay upon accepting a role with another retailer. And on her last day, they still left her a pile of work that took until 5am to finish...Greedy and unprofessional.
4) Sad to see a whole lot of honest employees lose their jobs. Although the owners of F21 had a big fall coming given the amount of greed and indifference they expressed to employees https://www.latimes.com/projects/la-fi-forever-21-factory-wo...
Those are different things, right? From what I understand, Apple works on a phone for about 3 years, but they cycle every year. You can have multiple 'prototype to street' cycles running that deliver a new collection every 3 weeks. I'm not sure that's how it works in fast fashion, but I wouldn't be surprised if it does.
The caveat is that this is just what I read. I wear 501s and a non-print shirt (yes, sadly, it's sometimes black) to the office every day, what do I know?