There seems to be plenty of good, free UML tools. I hear about UML tools being used by large organizations, and they seem to have plenty of advocates. However, in my career I have never seen them used beyond "dabbling". Now, I have seen many UML diagrams drawn on whiteboards, and I use them myself all the time, on paper, to think about problems.

I've also seen articles such as this one claiming why developers don't use UML, but the arguments just don't land with me.

Frankly, this seems like an opportunity for a start-up if one can figure out why developers really don't use them, and solve those problems.

So I'm asking anyone here who has attempted to use UML tools in a team, and stopped, this question: "why did you stop?" I'm especially interested in experience from agile teams.

I am looking for concrete experience, not hypothetical opinion. Thanks.