I mean, yes, you're missing something, the first and foremost, Internet. :) Its sole purpose was to solve the information access problem in a decentralized way. That was the rationale behind the ARPANET project.

Then, DNS came, which is also a decentralized solution to the name resolution problem. BGP routing is also similarly decentralized. World Wide Web itself is decentralized. IRC is decentralized. These technologies predate almost everything you mentioned.

I agree with your sentiment that it's mostly a cycle. I just wanted to emphasize that decentralization had never been a novel idea. We've always had decentralization, it's not like a new revolutionary thing as it's presented. That's my point.