Really. It's amazing that not one cordless tool mfr shares a standardized batt attachment with another 40yrs in, Snap-on can't settle on one in-house, DeWalt had a redesign but at least sell a batt/charger/adapter kit. I was using the old 9v Makita's in the mid-'80's when they were the only real game in town, but things change......Why would you need to change out brand new batteries?
You would buy a car that had the standardized batteries as original equipment.
There's likely a market for cordless tool battery adapters that let you use currently produced batteries in tools they are no longer marketed for.
I've made my own, but if you could sell a low priced (it's "only" plastic and a little brass/copper) adapter and current production batteries could be had cheaply enough, it may be the impetus for not simply throwing away a set of otherwise nice and functional tools simply because you can't buy batteries with the proper connector.
We seem to have stabilized on 18/20V for the past several years, so that's a plus for the above plan.
You keep talking as if these are just large RC cars or cordless tools, ridiculous......
The performance, safety, & durability requires precise temp & current management. New HEV/EV batts that at the top are water-cooled, take special antifreeze/coolant, & need the complex system bled in an automated process that takes 15-20mins...and may have to be repeated twice before the vehicles sensors give the control module the"all clear" to operate. If it is not done correctly, the vehicle will jump into a "power reduced" mode, read crawling along.......a lot of these are under or in the floor, and just as big, weigh anywhere from 1/3-1/2 a ton as an assy. Full of sensors, coolant, relays, modules, etc.
You're still in fantasy camp Dude........