if women stopped buying pocket-less pants, they would cease to be sold in that volume… or rather, the best way for the general population to resolve this would be for a volume of disgruntled women to only frequent the few suppliers of decent-pocketed pants.

money talks, and they tend to sell what people buy… especially with these low-margin, high volume items. excess inventory is a big liability.

edit: a more specific answer to your question i guess would be, “women choose the silhouette of no pockets over pockets”… its about looks