True that, and I also believe that "there is no permanent in this world but change". Since Blockchain is only a creation of man, anyone with enough knowledge and power can easily modify anything. I also believe in the uncertainty of the future, who knows there will be another technology far more useful than blockchain technology that will render it worthless.
Blockchain tech is still young and currently trending, whatever lies ahead we never know until we get there. The real value of blockchain depends on the people who patronize or despise it. It might be worth the world or nothing at all. At the end of the day, it is the individual's valuation that matters.
We must admit that blockchain, at least version implemented in the bitcoin network, is the first successful realization of digital immutability. Whether or not it is completely immutable, it doesn't actually matter. It maybe just a first step of the big journey into new world of digital technologies where immutability matters. Technologies we have never witnessed before. That is why I rather value decentralized blockchains, because centralized realization don't have unique properties and look similar to databases. When you rename a file on your PC, it doesn't make it different, its properties remain exactly the same. What companies did when they started to use the word "blockchain" is just renaming the file. There is nothing special with using old databases, but they have been trying to make it more valuable by using the modern term "blockchain".