Not to mention all the upcoming competition in the genre such as Dual Universe and more.
I think that's the elephant in the room alright. Not Dual Universe in particular, but competition in the genre. Some games are already out, others in development, new ones are sure to appear. And each additional delay erodes a little bit of novelty from SC as either gameplay ideas or graphical engine features get implemented somewhere else. Already, the screenshots are pretty but no longer as special as they might have been 3 years ago. What will it be like in 2/3 years when new graphics-focused games come out? I'm not sure how they'll get around that.