I don’t think Musk thought this through before speaking out.
I believe he understands that oil drives the economy s well as 99% of the cars on the road. A recession will not be good for stocks with astronomical multiples, nor good for sales of “luxury” products to the middle class (which he hopes to accomplish in the next few years.)
While I am generally skeptical of his long-term thought process (but admire his remarkable accomplishments) I think he’s pretty aware of the risks of a long term oil shortage to the global economy.