That is true. In the last year's study there were about 5 coins, which come down (almost) to zero. But some of them had made way more than 1100% profit. That article was also written here on steemit. You should take a look at that, it is really interesting. ;)
https://steemit.com/cryptocurrency/@ashr/diversification-case-study-usd100-on-each-of-top-100-a-year-ago