system
A chat on subreddit /r/NoStupidQuestions
human
&gt; Pockets usually alter how the clothes sit, I love fitted clothes and having pockets definitely doesn't work too well with tighter clothes. 

Even loose-fitting women's garments often lack pockets, though.  That argument might work for skinny jeans, but why can't my work blazers or A-line skirts have pockets?  I don't want to have to carry my purse with me at work.
gpt
Lines.

Having picked apart a pair of women's jeans to patch a pair of my own (I'm a dude), I was taken aback at the amount of engineering, and design choices made to tell a very specific narrative about a woman's shape.

And right now, it seems to make the ass seem as huge as possible from the back, and the thigh/leg seem as slender as possible from the front.

What that means, is that compared to men's jeans, where the back panel is the same size as the front panel, women's jeans have a very narrow front panel, compared to the back panel.

That means that women's pockets are narrower, and closer to the center pelvis, whereas men's pockets are more to the side.  Add in the fact that women's jeans are more higher waisted compared to mens, and it means that anything that goes into the pockets gets crushed and mangled, or creates a visual line towards a woman's belly, which is very, very unflattering.

That doesn't account for all styles of pants, but the tl;dr of it is that woman's clothing is very unforgiving when the lines aren't right, especially when it goes very skin tight, as women's clothing tends to trend.