(edit: here https://news.ycombinator.com/item?id=28243811 )
IIRC it went some thing like:
1) Declare a ludicrous "pie in the sky" / "City on Mars" goal.
2) Use that to inspire, hire clever but starry eyed people who will work 7 days a week in service of that.
3) Iterate rapidly on do-able things in the general direction of the goal.
4) Reach some some point that's far from the original goal, but is still a huge achievement (e.g. re-usable rockets to LEO).
5) Profit!
6) Use the profits to start again, with another field that has synergy to the last (e.g. if you have electric cars, then add solar panels and battery packs)
In terms of humanoid robots this makes sense, the "10% to the goal" point is useful, and ties into the space plan. Robotics and space have synergies.
Note: original post calls the big goal "relatable, unoriginal" - this is a feature not a bug: to inspire, pick something that people already understand. Something that you don't have to explain.