Women do talk a lot about the lack of pants in pockets, but they don't actually seem to buy pants with pockets.
This is a perfect example of revealed preferences. Pants with pockets are out there for sale. They're not even rare. Especially in the modern world where you can order clothing online, it's easy to find and buy just about anything you want. Women could exclusively buy pants with pockets, but they don't. Why not? Probably because pockets are important, but when it comes right down to it, pockets aren't as important as other things like fit, style and price.
I'll definitely agree that the major fashion houses might refuse to make pants with pockets. For them fashion is the only thing that matters. In fact, they'd probably only add a pocket if they could justify as a part of the style. And, there are going to be other designers who just copy the major fashion houses, maybe with minor modifications. But, they might not put in pockets because they're trying to copy the major designer.
But, do a web search for "women's pants with pockets" and tell me if you don't find all kinds of results.
As for societal norms, I completely agree that the current world is one where women are expected to be pretty and men aren't. That wasn't the case in the 1700s where men wore makeup, tights and high heels. But, in the current world, it is women who society expects to make themselves look pretty, where that's not expected of men.