In my opinion, the altcoin will remain in the market, but not a few altcoins can not survive in the market. All of this depends on the ability of the altcoin to defend itself in the market and gain public trust. I am sure that if an altcoin has great technology and is capable, then the altcoin will still be able to survive. Therefore a new altcoin should emerge with unique technological innovations. If an altcoin only duplicates the technology of the previous altcoin without having special advantages then these altcoins will be easily excluded from the market. Therefore, as an ICO developer, I suggest making a strategy to the sustainability stage of the altcoin when the ICO timeline is complete.