UML is closely associated with Object Oriented programming. In the 2000s, OO programming was all the rage, and having a mental notebook of “design patterns” was

UML is closely associated with Object Oriented programming. In the 2000s, OO programming was all the rage, and having a mental notebook of “design patterns” was considered the hallmark of a real software engineer. Since then, OO has lost a lot of its luster, the languages most associated with it like Java and C++ are considered somewhat clunky and uncool. Functional programming took over as the “smart” paradigm to talk about, even if in practice most popular programming languages borrow a mix of imperative, OO, and functional features. UML was also popular in a time when you could make a SQL database and just use that. The introduction of more database varieties complicates things. Besides OO, UML was also strongly associated with “visual” programming done by non programmers. This paradigm is doomed to be reinvented and pushed as the next big thing every 3 years until eternity, which we currently see with whatever the latest no code trend is, but in the 2000s was associated with UML. Finally, language independent data formats like JSON, Thrift, and protobufs got popular. Why make a UML diagram when I can just make the actual data structures then immediately have that as a binary format? To the extent UML means “data modeling”, people still do that. But it became associate with a lot of cultural baggage, and most of that baggage was on the losing end of a lot of technology mindshare battles.