The Lightning Network is for real, it's happening guys. I don't think the top altcoins will disappear but many will go the way of the dinosaurs, no question about it.

Check my hands-on first experience with it. It's still rough around the edges but quickly ironing out the issues: https://steemit.com/bitcoin/@cryptoeagle/my-first-experience-ever-with-bitcoins-s-lightning-network-pains-and-glory

Also check this Wikipedia page for a very similar massive tech dying process that happened not so long ago in history: https://en.wikipedia.org/wiki/List_of_defunct_automobile_manufacturers_of_the_United_States