Blockchains as such are a fundamentally sound technology that meets real needs. So cryptocurrency is going to survive.
Will ALL cryptocurrencies survive? No. Some of them will become historical footnotes, and not necessarily because there's anything wrong with them -- it's just that with so many coins out there, the market is likely to choose a few overall winners, quite a few niche markets, and lots and lots of "yeah, nobody cares about this ones."
I concur with the author, with one caveat: Get your portfolio in order with coins that you can make a good argument to yourself will survive and thrive, and then HODL.
Personally, and this is not investment advice, my own small portfolio is mostly Ethereum, with my Steem HODLed as Steem Power, and with very small positions (too small to worry about exchanging) in Bitcoin Cash and ReddCoin. I also have a little bit of BTC, aka Old/Wrecked Bitcoin in an account that I can't move it out of just yet (a place that pays me for stuff in BTC and has a minimum withdraw amount), but that I will dump when I get a chance.
Good point you made there, I definitely agree that you should only invest in projects in which you believe can survive and make a difference in this world. I might add this to my article when my bandwidth fills up more! Thanks for your comment Thomas!
My portfolio is very diversified but I also have most holdings in ETH. I'm hoping my altcoins will recover soon though, it hurts to see everything bleed this hard. Stay strong and keep HODLing, the glory days will come back!