Cybertruck...or how NOT to build a vehicle

[Elizabeth Greene]

Im still gob smacked that no one has thought to retrofit pertrol/derv cars with electric motor and battery packs, wouldn't that get dirty fuel cars off the roads quicker.
Why have Hydrogen cars been shelved in favour of battery ones, no money to be made from the average Joe perhaps

There are several reasons. The biggest one is that Hydrogen isn't a green fuel. Hydrogen made from water with electrolysis could be low emissions if the source for electricity was clean enough, but the vast majority of hydrogen today is cracked out of natural gas. Combine that with difficulty in compressing and storing it, much lower energy density per volume than gasoline, and lack of lubricity in the engine and it's not a promising technology. The biggest advantage of it over electric is that you can refill tanks faster than you can charge, and the physics of compressed gasses make that tricky.