Why would I spend an hour on buiding a diagram to generate code if I can type the same code in five minutes? I can read both. This is from real world experience with Rational tools.

I suspect the idea was to lower the skill ceiling to make it accessible to non-programmers or more cynically in a belief it would cut labor costs. It doesn't work out that way but overspeccing the wrong details is a persistent temptation, perhaps related to psychology of the leaders for reasons similar to micromanaging.

Either that, or probably thinking about huge systems with uml diagrams in the size of the last supper.

Together/J made a really good attempt at it.

So good that Borland bought them up and shit canned it.