I think the biggest difference between JavaScript and SQL is that there are things that SQL is actually extremely good at. For certain tasks, it really is the best language available, and not in the "least bad" sense but the "why would anyone even try to do this any other way?" sense.

To get that level of applicability, of course, you have to make your problem match the form SQL needs. For applications on its home turf, for example a simple inventory system, this can be both easy to do and beneficial (since if you're on SQL's home turf and you want to do something you can't do, there's probably a Very Good Reason). Unfortunately, this is not always easy to do, or even possible at all, and even when it is possible you usually need to know some basic relational algebra. (Tangentially, I am convinced that many of SQL's critics would be quieter if they knew a bit of relational algebra themselves, though I don't think that applies to this article.)

As you say, though, trying to make a tool do something it just shouldn't is the road to madness. The article's discussion of JSON in SQL is a pretty decent indicator of how that goes wrong even when it goes right. For further snapshots of the road to madness, the interested reader might examine C++, JavaScript, and a competent psychiatrist. Sometimes it really is time to move on, or at least add on.

Just adding that JavaScript is also the best at something - running code sandboxed - especially in a web browser. Like SQL for databases, JS has no competition for web development (because the web needs full compatibility, and adding another language doesn't have a good value proposition - just compile to JS) and thus is immensely popular.

Most languages have something they are the best at. SQL is probably THE language with the strongest value proposition - relational databases are even more important and ubiquitous than web browsers. But why doesn't SQL have any competition?

I would love to see an alternative to SQL in the style Jamie suggests. Maybe SQL would immediately not be the best anymore?

Half of the triumph of SQL here is the strength of the relational model, which rests on a solid mathematical foundation and is well and truly the best way to model the vast majority of data domains.

The other half is just having no meaningful competition in that one domain. So I agree with the author (and you presumably) that building something better on top of the relational algebra should be a priority for the profession.