It might be helpful to note that this article was written for the FT (as he mentions at the very bottom.) While it aphoristically may make a “pre out of you and me,” I presume neither the author, nor the subscribership of FT _are_ indeed (or wish to be) constrained to the language of a typical 10-year-old. Presumably the same would apply to the readership of HN.

We don’t know if the author _can_ explain it like we’re ten, but I think we can be reasonably certain they understandably chose not to.

The author can do that, but didn't for literary effect. And he can do that because his audience is FT readers, not 10-year-olds.

Ten-year-olds don't need advice on how to explain something like the listener is ten.

Good thing they never claimed to be writing in that style then. Not sure what you're working yourself up over here. Authors are allowed to write about a method of writing without having to apply it themselves.

Is "explaining it like I'm ten" a complex topic?