If the author is reading this, the most interesting thing about your article is that it creeps towards the recognition of something important (i.e. that data ordering and data permanence are quite different things) before it balks at the implications and adds unnecessary properties to its definition of a blockchain.

This makes the piece come across ideological. As a case in point, you write that the public aspect of a blockchain is what ensures its permanence but that is not at all the case. The public aspect is what guarantees open access. Open access in turn guarantee decentralization under conditions where decentralization is economically feasible. The only thing that guarantees permanence is the economic incentive structure that pays participants to store and distribute data.

We don't have a good taxonomy for discussing these ideas yet, but most people working on scale are beyond this. Ethereum is experimenting with rent. Bitcoin variants exist which have adjusted their genesis block manually. Some layer-two networks are designed be transient, while Saito uses a transient blockchain to put bandwidth-intensive applications directly the first layer. The direction of development in the space is tilting very clearly towards utility networks and disposable data-structures. The disagreement is over at what layer this needs to take place, and how to preserve things like open access while paying for things like bandwidth and storage.