Are we living in a computer simulation

This is a hot topic at the moment with many people having thoughts on the matter. My answer to the question is: of course we are not. The answer is depending on what is meant by a computer simulation, and here I am referring to a situation similar to the Matrix, which is what is usually considered in the current discussion. However, I think the discussion is not very different from what actually Descartes already had when he was discussing his demon and Kant with das Ding an sich.
Anyway, my arguments against the idea that we are living in a computer simulation are:
1. Evolutionary extrapolation. It is often claimed that extrapolating the current pace of technology advance indicate, on an evolutionary time scale, that there should be machines capable to performing these kind of simulations at some point. However, this is a logical error, because current pace of technological advance has not occurred on an evolutionary time scale. Thus, it can not be extrapolated on an evolutionary time scale either. There is no predictable way to tell what will happen with technology over long time scales.
2. Ethics. We know from our own civilization that once we get advanced, we also have ethical ruses. E.g. we do not allow for any type on animal experiments. I am guessing that the kind of simulation referred to in the discussion would be considered highly unethical, and not be allowed to be run.
3. Computing power. If the world is constituted in a way similar to ours. That is, the presumed simulated structure is similar to the world in which the simulation is run, then it seem to follow that it will be very hard to simulate it accurately. It is not easy to simulate it self.
4. Epistemologically. If there is no way to detect that we are in a computer simulation (actually Neo noticed in the Matrix), then the discussion is not a very interesting one at all. Since then we have no way to test the hypothesis. Further, is it not likely that if we are in such a simulation, that just by design, we would not be able to detect the boundaries of the simulation. Any "flaws" in the simulation would appear as how the world is constituted to us (maybe this is the reason behind cancer, chaos theory, the Republican party, ... and other crazy-ness).