This is my adopted long-term field -- though professionally I work as a bitcoin developer right now -- and those estimates are my own. 1-2 decades is based on existing AGI work such as OpenCog, and what is known about generalizations to narrow AI being done by Google and a few smaller startups. It is reasonable extrapolations based on published project plans, the authors' opinions, and my own evaluation of the code in the case of OpenCog. 5 years is what it would take if money were not a concern. 2-years is based on my own, unpublished simplification of the CogPrime architecture meant as a blitz to seed-stage oracle AGI, under the same money-is-no-concern conditions.

I don't really entirely endorse the algorithms behind OpenCog and such, but I do share the forecasting timeline. Modern work in hierarchical learning, probabilities over sentences (and thus: learning and inference over structured knowledge), planning as inference... basically, I've been reading enough papers to say that we're definitely starting to see the pieces emerge that embody algorithms for actual, human-level cognition. We will soon confront the question, "Yes, we have all these algorithms, but how do we put them together into an agent?"