Coins that are just trying to be a currency will die out, there are a few which will have a network effect and the features that are useful to people, the rest have no purpose and will go to zero value.

Platforms that provide particular services will survive and flurish.  Much of this will happen ontop of existing protocols like ETH, or Bitcoin, but there may be uses that are specialized enough they will need their own type of blockchains.   Blockchains as databases have a particular use, so there might be certain types of business environments that need their own financial database, so these types of chains will probably only grow from here.