Yea, I know all about the training and First Derivative. My employer also hired them.
In their defense, every First Derivative KDB+ consultant that I worked with was very sharp and an excellent teacher. They really knew their stuff, and First Derivative is no small part of what has made KDB+ so successful. However, even with their excellent pedagogy, most of my co-workers were totally lost/weren't willing to apply themselves to learn q/kdb+ well.
Here is another way to think about it: many people can't ever get their heads around certain conceptually difficult topics, say, measure theory or quantum physics. I don't think kdb+ is nearly as hard, but it seemed that way looking at my peers who were no slowpokes.
> ... came back buzzing with excrement