system
A chat on subreddit /r/NoStupidQuestions
human
Because functional pockets make pants look bad. If you put something in them you have an ugly bulge. If it's heavy it will sag the whole thing. Hell, to even have a fucntional pocket in the first place you can't for example have skin-tight pants that women like so much.

So whenever women are confronted with a choice between functional pockets that will make them look worse and no pockets they will pick the latter most of the time, and the market reflects this.
gpt
Correct. This argument by women for pockets always perplexed me. It always seemed like there was a collective worldwide cry by women to have pockets in their pants because there has been a conspiracy by the pants Illuminati to oppress pants and dress pockets. 

And when I heard women complain like this I thought “Sheesh just puts pockets in pants! Is that too hard to do for women?” And I thought, “Why wouldn’t there be pockets in pants for women if that’s what they want?”

But no. It turns that women don’t really want pockets in pants and dresses.  Maybe it’s the same very vocal 4 women who want pockets.  Because if this was a product that sells it would be on the market.