More cushion for the pushin........thats how and why :D. Also women are generally fatter now than ever before. And the first place fat goes for women while developing is the breasts, and booty.Also our modern lifestyles do not create ideal bodies. We are no longer in the fields digging out rocks bare handed then moving them so we can make a potato expansion of our farms lol. Robot sweepers and moppers now. Thats going to start weakening peoples Core muscles. These items of convenience are literally what keeps us fat and weak. Because day to day chores used to be quite labor intensive, back when women and men were generally much fitter.