I think part of the problem is that databases can have a mix-and-match of features, and it is hard to classify one database into a single category. I think the article does little in actually helping a developer make an informed decision about what underlying data structures actually fits best with their scenario.
To give some examples, CockroachDB both has column-families and NoSQL characteristics. A column can be specified to be a JSON column, and it can have an inverted index.
Or MemSQL has both row-based and column-based tables, and they use an unorthodox index called "skip lists".
CockroachDB and MemSQL both have different applications and characteristis, but they are just cluttered under "NewSQL", as if it was just was some kind of "SQL but better".
> I wish more time would be spent talking about the underlying algorithms
That's precisely the difference. How they store data is fundamental to what kinds of operations are fast. A row-based and columnar database can look rather similar (PostgreSQL/Redshift). But the performance characteristics are far different.
Did the article come up short?