> Demis Hassabis has recently given an estimate of human-level AGI in 5 years

He said 50% chance of AGI in 5 years.

Yes, and I wonder how many "5 year" project estimates, even for well understood engineering endeavors, end up being accurate to within 50% (obviously overruns are more common then the opposite)?

I took his "50% 5-year" estimate as essentially a project estimate for something semi-concrete they are working towards. That sort of timeline and confidence level doesn't seem to allow for a whole lot of unknowns and open-ended research problems to be solved, but OTOH who knows if he is giving his true opinion, or where those numbers came from.