I do think there is a "generational" (used loosely, as the generations here are much shorter than what we usually think of in terms of generations) component to it as well, just in the sense that what you consider the "software/firmware/hardware" guys were much closer to being the entire set of developers up until the early to mid 1990s than they are now. The concerns of today's embedded developer were the concerns of virtually everyone back then.

As a 39 year old, my list is virtually identical to jijji's and most people I know who program and who are about the same age or older would almost certainly cite a huge overlap if not the exact same list.