You only need to look at the specifications: https://www.omg.org/spec/UML https://www.omg.org/spec/UML to realize that it is very heavy weight. The tools that i

You only need to look at the specifications: https://www.omg.org/spec/UML https://www.omg.org/spec/UML to realize that it is very heavy weight. The tools that implement it beyond mere pretty drawings take a lot of effort to learn and come with Enterprise grade prices. For large projects it quickly becomes very difficult to effectively manage models. Once you use the round-trip-engineering features of some tools, you either improve the code or the diagrams, but there never is enough time to do both well. As a communications medium it is an extremely specialized jargon. Outsiders, generally, require lots of hand-holding to gain even basic comprehension of what is documented. Based on the foregoing, UML never was and probably never will be cool, or even particularly useful. Ok, some subsets of UML are effective in larger, complex projects, e.g. modern fly-by-wire avionics.