Except DVD is not a unified standard, not even at all. For the first few years it had to compete with VHS, LaserDisc and that defunct DIVX. Then by the time Blu Ray came along which also had to compete with DVD, and HD-DVD for a brief period, there was also Netflix, and then Roku, Itunes, and then Vudu, Ultra Violet, and the list goes on. Even when VHS was still fairly new it was not in the market all alone it had a whole decade where Beta Max, LaserDisc, CED, and Video8 all made attempts to enter the market. YES VHS was the dominant format for a few years and same with DVD but they were never even close to a single standard everyone bought. Those are just the most popular and semi-successful companies there were dozens more.