Companies that once revolutionized and dominated new industries – for example, Xerox in copiers or Polaroid in instant photography – have seen their profits fall and their dominance vanish as rivals launched improved designs or cut manufacturing costs. In technology, the cassette tape replaced the 8-track, only to be replaced in turn by the compact disc, which was undercut by downloads to MP3 players, which is now being usurped by web-based streaming services. Companies which made money out of technology which becomes obsolete do not necessarily adapt well to the business environment created by the new technologies.