$1/2 Trillion profit, 3000HX robots, page-54

That's a great bit of history! And yes I think you're spot on in that this has ended up way harder than they thought. First robot slated for sale in 2017 and at least 2020 before it's proven to work outdoors.

Not sure anyone would buy a robot for building houses until it's shown to be able to operate outdoors on a building site.

And you wouldn't go into commercial production of the robot until that was proven lest you had to retrofit a heap of hardware.

Presuming they do build outdoors next year and have the design finalised then 2021 would be a reasonable timeframe to build additional units.

Not that it's the model any more but that would also be the timeframe for delivery of a commercial robot, four years after initially thought from the 2016 projection.