There are so many coins, but many of them just a copy of anothers. Why they waste their time for nothing? 
People try to create their own coins for marketing and to develop their own business. These people are called developers and they need to promote their platform. As other people support them, developers would earn more profit.
They all dream the same thing like us, to get rich. They think that if they own their coin and even they can make one coin a dollar, they will have millions of dollars but of course it is not a easy thing.