But I'm not talking about any distributed data sharing such as p2p bittorrent with hash verification, or git/github, or NNTP Usenet, or the distributed accounting system you worked on, etc. For purposes of this thread, "blockchain" is synonymous with decentralized trust which I believe is how it's usually used.

I can agree that blockchain didn't invent "decentralized data sharing" but that's not relevant to my point.