The fashion industry might be trying to curry favor with average size women by calling them petite.
No, that’s not what’s happening. The average woman is not petite-sized. Most women wouldn’t want to be this size. Petite sizes are hard to find. There’s not much selection.
It’s not so much about height. It’s about other measurements. Size P is not only shorter in the length of pants, but also smaller in other measurements, such as the arm holes in tops.
I don’t know how this subject started, but there it is.