[narnianal]

When you read "blockchain" always think "decentralized: cool; wasteful: not cool". I think it was designed like this on purpose, but besides creating a value store it's not a reasonable choice. Also it's a list structure, which inherently does not represent reality. E.g. if you and I both agree about the blockchain until September 13 2018, but afterwards have different opinions about how it should go on, there is not way to present that misunderstanding in the technology. (It's possible if you put an abstraction layer on top, but that's another topic. You can put almost all protocols/algos on top of each other.)

So it's wasteful and can't represent reality well. So it's quite limited to how far we can use it as a whole species.

It's less the Amazon of algorithms and more the Myspace. In 15 years it will still have some impact in the abstract sense of how it influenced technology, but blockchain itself is unlikely to still be there.