I'm in Scotland at the moment and seeing the representations of men in kilts in art and statues makes me wonder why the rest of the Western world views skirts as non-masculine and embarrassing. I'm genuinely jealous they get to wear these wonderfully liberating attire without judgement.
This has already been answered. It comes down to pants are much more practical for labor, warmth, and riding. Women have stuck to dresses because they did less working and riding, and dresses are much better for periods.