. . . and men’s buttons are on their right because they preferred to dress themselves.
Well, not exactly.
First of all, buttons are seldom found on women’s clothing before the nineteenth century. Mens’ clothing, yes, but women used ties, hooks, and other fasteners more than they used buttons. With most clothing made by the women of the house or, in the case of the wealthy few, by dressmakers and tailors, individual preference prevailed in positioning buttons. There was no standardization until the Civil War era when the manufacture of uniforms began on an industrialized scale. That is probably when buttons became more or less standard on the right for men.
Curators who deal with nineteenth-century women’s clothing report that they have seen buttons on both sides. No one is willing to go out on a limb on this topic, but it seems that the button-on-the-left for women’s clothing probably got started in the early twentieth century with the rise of women’s ready-made garments. And since women buying ready-made blouses would not have been among the wealthy few (who continued to use dressmakers), the argument about maids is illogical.
Besides, who says wealthy men preferred to dress themselves and wealthy women didn’t? That idea is totally unsupported by fact. What were all those valets, houseslaves, and manservants doing, anyway?