You guys do realize that the UE4 shots were rendered on a Titan X? I doubt that anyone has one....although, the demo comes out in a week, if someone manages to get it running on a mid-range pc, I'll take back my words.
As a UE4 subcriber for 9 month or so, almost all demos release by Epic that I downlaoded can run well on a decent PC: They uusally do not release demos that only top end PC can run.
You have to remember these demos are not just for wow foctor showpiece for end gamers, but also design templates that developers can use as a starting point/template for tuning & learning. Making a demo that can only run well on Titans do not make sense.