> managed to (mostly) not back into kids for over 100 years, without rear cameras

They reckon the mandatory backup camera law saves 95 lives a year.

Getting out of the car would save 95 lives, too

> Getting out of the car

Some cars do have remote-control drive features these days, so you can reverse it from outside the car, but that's a super high-end feature (designed for getting in to and out of extremely tight city parking spaces) and relies on the chips that are in shortage, so that's not a solution.

We are but muggles, so I don't think we need to worry about teleporting children appearing in the time it takes you to get back in the car. You know your blind spot is clear and can see where your future blind spot is now.

This is like arguing against seat-belts because you think you can brace yourself sufficiently.

Seat-belts are have basically no downsides. Backup cameras trade back over accidents for accidents involving cross traffic.

Kids also used to stand in the back while being driven around. I certainly did. Not only were there no car seats, there weren't even seatbelts in the back. Putting kids and their toys in the back of a station wagon for a road trip used to be a thing. Everyone mostly made it out alive, and yet we still have laws against all of the above now, everywhere in the world.