These contrived examples seem appealing at first, but when you start having deeply relational, nested data, with M-M joins, the relational model is much less appealing. SQL is just one popular declarative approach that people are familiar with and is reasonably easy to read by non-devs for simple things.

Modeling all data on SQL is definitely an improvement on most ad-hoc data manipulations people do.

But say you want to stream updates from your SQL queries, this is something the relational model and SQL dbs are not great at doing efficiently and actually hinder.