I have a good friend who believes reality is subjective - that events may be determined more by where you choose to focus your attention, than by some universally consistent instance of the laws of physics. If that is true (which I think it would have to be, if we were an attention-oriented simulation like you describe), then it seems pretty difficult to come to any conclusions at all. If causality doesn't have to be globally consistent, it should be possible to "break" the laws of physics and get things like free energy or faster than light travel. I highly doubt Mr. Kurzweil would want to entertain such notions, since the possibilities are already so exciting even if we assume that universe is objective (i.e. the laws of physics apply everywhere simultaneously).

Of course, the possibility of us being the only intelligent species certainly would depend on whether we're in a simulation designed specifically for us. But I don't see any reason to prefer that idea over a simulation with 1 billion intelligent species per galaxy. To prefer the former seems no better than assuming the earth is the center of the universe.