The external dependency of the petrol car is the production of petrol. Huge amounts of global state focus goes on making sure there is a garage near you selling petrol at a "reasonable" price. I mean wars, repression, pipelines that have their own countries and armies, vast ships across oceans, bending millions of people globally to the needs of us users - "the spice must flow" is a very apt phrase.
Something I do not hear much about but must be hitting military thinkers around the world is ... what happens when EV really takes over.
A tesla powered off my roof can take me to the local supermarket but can you drive a main battle tank on Lithium ? How long does the recharge take from solar cells? How do we fly a helicopter when the only people doing fracking are doing it for military?
Who runs a oil refinary just for the US Navy? And what if the US Navy decides not to sell you their oil from the only working refinary?
The impact on mechanised warfare of the change to EV is something I don't hear much about.
The point is that once everyone is in an EV car, your traditional car hits all those problems. At some point the western world will think "phew we can stop paying Saudi and just drive EVs from our solar cells" - and the whole fucking thing collapses. That's somewhere around 75% of cars being EV.