Thanks for the article, however I have heard those claims about blockchain being not truly immutable system. These are not baseless at all. But you can claim the same about everything we have today. Every notion can be disputed. Any truth can be viewed from different perspectives, you can find flaws and shortcomings absolutely everywhere. Everything is relative, there is nothing absolute in the universe. Even universe itself can be destroyed by big bang, in the same way it was born. So, while we are talking about immutability of blockchain, we can't predict future of humanity. If humanity refuses the idea of bitcoin, it will definitely fall apart, its immutability will be gone for good. It is people who have to decide whether they need immutability or not. After all, bitcoin and blockchain were created to serve people, so let people to decide what to do.