1) US military builds up arsenal of autonomous killing machines and nuclear missiles
2) US military connects all of these to the Internet
3) US military creates a powerful AI which takes control of this arsenal (whether it was put in charge or hacks in seems to vary across the movies)
4) AI "becomes self-aware"
5) AI tries to wipe out humanity
Almost all of the discussion around this focuses on step 4, either by asking if/when an AI will "become self aware", or by trying to explain why that's meaningless and/or unlikely.
Meanwhile I think the real dangers are steps 1 and 2, which seem to be proceeding without much public outcry.
Yes, there are rogue AGI scenarios which end badly for everyone; but there are also issues of hacking (state-sponsored or otherwise), and/or terrorism (homegrown or otherwise).
It may have made political sense to build up ever-larger nuclear arsenals during the cold war, but these days it seems like that's just increasing the risk of accident or misuse.