Damn dude, I didn't ask to catch strays like this :(
https://www.hexagona.com/fr/sacs-bandouliere-sacs-banane/553...
I've heard many women complain over the years about the small pockets, but my assumption (possibly very wrong) is that they might not buy a pair of jeans if giving them full sized pockets made them significantly less fashionable (i.e. they'd get less utility out of them).
Talk to those women and they will admit there are many clothes for women with pockets, just that those doesn't look as good so they are searching hard for good looking clothes with pockets which basically doesn't exist. They rather buy clothes they like without pockets than clothes they find ugly with pockets.
Otherwise, the company(ies) that don't create purses don't make more money selling purses + pants.
Of course, there could be a new company that makers neither pants nor purses that gets into the pants making business.
---
It's aesthetics, pockets don't make a woman's figure slimming so they don't sell as well.