Something feels very,very wrong that Elon Musk is on the left-hand side of the chart, and Ben Goertzel on the right. I'd reckon that Elon Musk is a more reliable source about the timelines of engineering projects in general (with no offense meant to Goertzel). Maybe this axis isn't measuring the right thing?
This is a good point, and I added it to the penultimate paragraph of the "Caveats" section of the piece.
http://reducing-suffering.org/predictions-agi-takeoff-speed-vs-years-worked-commercial-software/