Look at electric cars. We've had them longer than ICE cars but they've never really been viable for most cases up until recently. It's not like we just realized we could run a car on electric motors, it's that battery technology has only recently gotten good enough that we can pull a lot of power from them for a long time before they go dead. Improvements in electronics have reduced the size and inefficiency of the components necessary to charge the batteries too. Trying to charge a Tesla off a gigantic linear power supply would be ridiculous.

The people building DIY electric cars in the 90s were using lead acid batteries charged with very slow trickle chargers, not because they were ignorant, they just didn't have access to the better technology we have now. People 50 years with some sort of cold fusion battery from now will look at our crude electric cars running on chemical batteries and laugh.