There are so many coins, but many of them just a copy of anothers. Why they waste their time for nothing? 
The reason why people create their own coin is "MONEY''. They create also their coin to compete to the other coin to gain more investor. And also they create their own coin because they thought that the coin they create is much better than the other coin.there are the projects where ICO makes perfect sense as a next steps in their company life. But most of them are just artificially made up crowdfunding campaigns to earn quick funds