You realize clothes are more than just waist sizes? Pants, for example, need to account for waist, hips, thighs, and length. All of these are very very different ratios on women of different body shapes.
And what you've said actually confirms that what I said is accurate - women can't walk into _any_ clothes shop and find clothes that fit, which is what the poster I replied to said.
Plus, some of the data there is not consistent globally. I don't know a lot of the brands there, but Uniqlo is one we do have and they do not do 3XL in women's clothing here in Australia.
It's also linked to the modern trend of having tightly fitted clothing. You don't have this issue with skirts, or wider, pleated pants with a high waistline. Those clothes were the norm before the 60's, since it's much roomier and allows to fit a wide range of body types.