I think it failed for the same reasons that visual programming languages fail. Things that look good on a PowerPoint slide don't scale. Eventually you're forced

I think it failed for the same reasons that visual programming languages fail. Things that look good on a PowerPoint slide don't scale. Eventually you're forced to buy an enormous plotter just for printing your diagrams -- which you tape to the wall, and watch them get out of date. I'd say that the final nail in the coffin was NoSQL databases. Everything about programming shifted to rapid, iterative development. Data integrity goes out the window; you just write your programs to be tolerant of data format changes. The quality of your data sucks, but if you botch a few orders, hey, that's just web scale. Move fast, break things. It was dead before NoSQL, and Big Data stomped on the ashes. Lots of data, mediocre quality, but good enough for the Silicon Valley work. Serious Software Engineering shifted to being about scaling, supporting vast numbers of customers with vast amounts of data. You have to put it elsewhere to do any analysis, and that analysis is probably at least partly wrong, but if it's within a couple of decimal points it's likely good enough. There are places where data quality still matters. They could use UML, but it just wasn't information-dense enough to inspire the kinds of tools you'd need to make it really valuable. Like, reliable two-way transitions from your actual implementations and back. It would help if you had a good object-relational system, but that turns out to never quite work either. The differences in approach feel like you can harmonize them, but they turn out to be like translating human languages on a word-by-word basis. Even if it works, you hate it. Anyway, that's just my $.037 (inflation adjusted).