Right. Attempting that workflow would be crazy without language support. But at the same time, proper languages that have operator overriding and custom types

Right. Attempting that workflow would be crazy without language support. But at the same time, proper languages that have operator overriding and custom types make that kind of thing trivial - look at how many languages have a Maybe<T> these days, which is basically automating that process. The fact that doing it in SQL would be suicidal shows that, while SQL was a brilliant language for the '70s... it has not evolved nearly enough.