Each cryptocurrency was created to serve a purpose. For bitcoins used to pay etherum is used to deploy smart contracts. Other cryptocurrencies born later have many advantages and are better supported by the programmer but still cannot replace the previously created cryptocurrencies. The problem is user demand, the popularity of that currency. We have too many ideas and overlap each other. Copying ideas of projects will lead to competition.
Currently the majority of cryptocurrencies have held an ICO, IEO is still in the stage of the idea of ​​no real product. The market is in the purification phase. We will have to wait a few more years to see results.