There is another question in this context. What would increase (decrease) the probability of the S event? Clearly the absence of another Earth despite of the Kepler's observations - increases it. What about Watson success? The fact we have no 10 Ghz processors?

Which are those relevant facts or events, which do influence? Can we say in a year or two - yes, since Wolframalpha manages it's own code, a self optimizer is highly likely in the next 10 years?

I think, one cannot do those estimations without pondering these.