Eg, when batteries are heavier than petrol, carrying enough fuel for a 200 mile journey every time you go to the shops doesn't make any sense. We need smaller, lighter vehicles for the vast majority of journeys. Scooters, electric bikes and trikes but also much smaller trucks for deliveries and tiny cars for people who can't use transit or bike-type vehicles (older people, infants, disabled people). Self-driving makes some of this more doable.
As vehicles get lighter, there is a virtuous circle where they need less fuel just to transport their engine and their fuel around. EV motors and drive trains should usually be lighter than ICE vehicle ones so this all helps.
A vehicle which can transport a whole family plus suitcases, camping equipment or Christmas presents several hundred miles in a few hours is a great thing to have, but we just shouldn't be using them routinely for urban and suburban journeys of a few miles, transporting 1-2 people and/or a few bags of shopping. Same with a truck that can fit half an apartment's worth of furniture.