> There are other models as well eg datalog, but popularity is a factor of many things
The lack of popularity is also a reflection of how the string of next best things have failed to actually deliver on their promise, accompanied by the lack of a rational argument to adopt them instead of using a time-tested technology.
What time-tested technology are you referring to? I'm only talking about the SQL language -- not the relational model, not the RDBMS engine, not the drivers.
The SQL language is just an API to the total engine; the majority of its value derives from the relational model; the value of the relational algebra is not being questioned. Only the particular interface to describe the relational algebra.
The power of the JVM is not the power of the Java language. You can have other languages make use of the same power Java has access to by targetting the JVM, and as a programming community we accept that just fine (and we also accept that despite Java having many known flaws as a language, its status as a first-party Oracle interface to the JVM, and its position within the status quo, makes it extremely difficult to upend; but that hardly implies Java is some perfect language, as most HN users will trivially acknowledge).
In the same fashion, the SQL language is (ideally) decoupled from the RDBMS engine; it can be replaced. But in practice, they're not so decoupled, and SQL has been consistently the only first-class interface to the engine, so like Java, it (can) enjoys far greater ubiquity and stability from the quality of the underlying tech, than the language itself may deserve.
So once again; popularity/stability of the SQL language is not (necessarily) exemplary of the quality of the SQL language. It's much more likely that it represents the value of the RDBMS, and the relational model (which I don't think anyone is arguing against), and the SQL language enjoys a free ride by being the only interface thats even offered.
I mean hell, just read the article. It has trivially observable flaws in its design and semantics (like stuffing a 3VL logic into a 2VL language). EdgeQL may or may not be the optimal solution, and I'm not arguing (or interested in arguing) one way or the other on that, but I don't see how anyone can reasonably argue that SQL's ubiquity shows its perfection, when it's so clearly imperfect (because those flaws are being very directly pointed out).
The lack of popularity is also a reflection of how the string of next best things have failed to actually deliver on their promise, accompanied by the lack of a rational argument to adopt them instead of using a time-tested technology.