It's on the same timescale as the European Blue Brain Project (and also Kurzweil's predictions, if you put any faith in that). If you believe that this an information technology that has an exponential growth, it's not a sufficient objection that we're far off now. The same objections were raised for the Human Genome Project, which was far from completion most of its duration, but followed an exponential growth and completed on time.
Yes, but you only have to double a megabyte 30 times to get a terabyte. That's a better perspective to take when dealing with exponential growth. Of course, the genome and the brain are different things, but the point remains that if you believe this will have an exponential growth, being far away from solving it is exactly where you expect us to be right now. And even now, we do have quite good computational models for certain small parts of the brain.