Altcoin disappearance on the market is very obvious because there are over 2000 altcoins existed and counting already. I could say that 70% to 80% of them are trash coins which should not be held for long term holding because they will disappear surprisingly specially if there are no trading volume coming. I saw many altcoin disapperance specially when we experience the bearish market last year. We just have to keep an eye with them.