Ya I'm gettin that....except this looks like even more than merely 2x.
I honestly watched that trailer and thought it was CG. Until I saw the OP, no way did i think that was in-engine.
The issue is that PC hardware is and will always be underutilized due OS, API, abstractions layers, multitplataform/hardware engines, drivers, etc.
Even fixed hardware like consoles have overhead.
If you really use low level hardware language (like Assembly for CPUs) you will see how powerful and fast these PC hardware are... they are just heavy underutilized.
And more the hardware get strong... more the unoptimized the software will get... just look at the old languages to have a ideia:
Performance: Assembly > C > C++ > Visual Basic >>>>> C# > Java.
Even the SO got slower with the time... just look at the Windows today compared with Windows in the last decade... Win8 uses way more resources than WinXP for example.