> quickly copying catwalk trends and getting them to consumers quickly
That's not much morphing, the goal is to have clothes that are quickly obsoleted for people who can now immediately keep up with the trends. Those people can be a minority of their customers but buy far more by volume, don't wear clothes until they wear out, and need to dispose of out-of-date clothes. If they push enough consumers to fast fashion then there is a vast excess of used clothes that need to be thrown out.
That's not much morphing, the goal is to have clothes that are quickly obsoleted for people who can now immediately keep up with the trends. Those people can be a minority of their customers but buy far more by volume, don't wear clothes until they wear out, and need to dispose of out-of-date clothes. If they push enough consumers to fast fashion then there is a vast excess of used clothes that need to be thrown out.