I think you analysis is correct. I also add that is related too to the languages, you point with Cobol, and I also add C, Pascal, Java, etc. When they have nul

I think you analysis is correct. I also add that is related too to the languages, you point with Cobol, and I also add C, Pascal, Java, etc. When they have nulls and limited to zero queries, relationships and data modeling capabilities is not hard to see that how they are is reflected in how the DBs are too. I honestly not know about sum types until a few years ago, neither have a clue how much useful they are, so surely even today many are in the same blind spots...