Elon Musk targets F-35 program, calls fighter jets ‘obsolete’ (youtube.com)
This is where things might go wrong. It appears Musk et al are the new guard. They're on their way in, and the reasons they're invited in are the things people really want them to do, fix various things. However, progress in weaponry seems a natural thing they'd do as well, now that you mention it, but this might not be beneficial. Weaponry is perhaps an area we want beurocracy and stasis, slow movement, inefficiency. Musk may be basically benevolent but what happens when the technology is in place but Musk isn't there? I think a lot of sharp people know a lot of things that would make violence, terrorism, manipulation, all kinds of things, more efficient and forceful, but just sit on the ideas, don't even breathe them to friends when the topic comes up.