I think lots of Altcoins will disappear because the value will be to low it already happened to a lot of coins and just will continue.
That is why it is really important to only invest in the really important Altcoins that actually add value to the Cryptomarket.

Because I don't think Altcoins will completely dissapear some actually add something new to the Cryptoworld or they work togheter with some of the main Altcoins.
But Bitcoin and Ethereum are definitely the main Crypto's which you should have but time will tell what the other Alts will do.