My iPad is smart enough to wait for a download until the battery is over 50% - or it’s plugged in. There is no reason a car can’t wait until it’s plugged in (and not moving).
And presumably, if it needs all that power for “sensors”, the sensors don’t have to be in use while the car is sitting stationery, so less power would be required.
My diesel pusher RV had 2 “starter” batteries, each with twice as much cranking amperage as the more common 12v batteries used to store power for the coach. There were two of them, although in a pinch you could get by with just one. They were larger, but only about 25% as much, so having enough power to run all the systems doesn’t seem it would be so insurmountable a problem.
And yeah, a more powerful alternator would take care of the issue while driving.