Bridesmaids don’t know how lucky they are. According to wedding folklore bridesmaids used to be dressed exactly the same as the bride. The idea was that setting up lookalikes would confuse any troublesome spirits in the area and make them unsure of who was actually the bride.
In Victorian times that tradition changed a bit and the bridesmaids wore white dresses but with short veils to contrast with the bride’s voluminous veil and train.
When society’s fears of evil spirits subsided and various new colors came on the scene, there’s no doubt that the bride had some fun selecting colors for her bridesmaids that made sure she would still be the fairest of them all. Only kidding.
Nowadays, the bride will discuss the dress styles in advance with her friends so that everyone (ok, almost everyone) is happy with the final selection.