It is a very interesting field - the concept isn't new - but the ARC is a specific small specialized cargo system - but others are looking at non orbital stationed items.
I know enough to know that the ARC loitering orbital drop ship won't work for humans (unless you tied it into a ISS type thing for crew habitat) and that seems to be a really poor way to have a contingency force sitting in orbit for years. The rest I am totally clueless on.
I suspect the cost would make those 20 C-17 look cheap though...