But physical space is inherently rivalrous, and a policy of "everyone runs a red light if they think they can get away with it" is going to have people being disastrously wrong sometimes.

I've actually ridden a scooter in places in SE Asia which basically work this way and it's... different. Less insane than it sounds, or looks like, but the rates of traffic fatality are objectively much higher.

This is why I thought it was interesting enough to comment upon.