I disagree that something with those properties is a blockchain. It's simply a distributed append-only ledger. The exact same functionality could be accomplish

I disagree that something with those properties is a blockchain. It's simply a distributed append-only ledger. The exact same functionality could be accomplished with a git repository they each pull/rebase/push between themselves... or with any of a number of append-only databases with WALs and synchronous replication, where each of them runs a replica.