[Robotbeat]

Assuming they meet 20,000/month in December 2017 as Musk says and ~40,000/month in December 2018 as you say, then linearly extrapolating between the two would still get you about 350-400k per year. Same order of magnitude.

[grecy]

And it seems likely if they can achieve 20,000/month in December 2017 they will be able to double that in 12 months.

I would expect them to double it faster, actually.