This is a good point, and I added it to the penultimate paragraph of the "Caveats" section of the piece.
That wasn't really the point I was getting at (commercial vs academic). The point was more that there is a skill having to do with planning and execution of plans which people like Elon Musk demonstrably have, which makes their predictions carry significant weight. Elon Musk has been very, very successful in many different industries (certificate authorities, payment services, solar powered homes, electric cars, space transportation) by making controversial / not obvious decisions about the developmental trajectory of new technology, and being proven right...
http://reducing-suffering.org/predictions-agi-takeoff-speed-vs-years-worked-commercial-software/