because in the long run their clones are better than the originals.
Nonsense. Zynga just used it's position and money to better advertise, brand, & connect their games together using facebook as a marketing channel. MS did the same thing with Internet Explorer. IE had the highest market share all these years NOT because it was better than Netscape, Firefox, & Opera. But because MS used their position, money, and installed base. Once at the top, a monopoly is hard to overthrow.