Earlier quoted context omitted.
He's not half-assing it, but he has Mars goals which are likely to distract him at some point. He is serious about his Mars efforts. At a certain point it makes sense for him to leave to focus on that, unless staying at Tesla also helps him hit his Mars goal by 10xing the resources he can dedicate to the effort.
He said he wants all this money just so he can fund colonizing Mars. So I'm guessing he'd take that money and just privately fund SpaceX, like Jeff Bozos is doing with blue origin.
If his goal is to colonize Mars and you want him to sell cars, a good way to do that is to say "sell cars for 10 years and we'll give you enough capital to do in the following 10 what you couldn't do in 20 from today."