@urlyman I think the root of the problem is even dumber: aesthetics.
Like, at this point, robots could be moving goods everywhere, if we were not completely hung up on the physical form of the automobile.
Like, if we established robot-only lanes and corridors, they could get around safely, much as cars having to stay in the streets works. But those lanes and corridors don't have to be car-sized, or on the ground.
Cars and trucks are approximately as big as they are, to accomodate both a human driver and a large ICE motivator. A robot that carries letters could be much smaller, and much faster, and in a rationally designed underground tunnel system, robots of all sizes could move all manner of things, the benefit being less and less need for people to jump in their automobile to go deliver a piece of paper, or pick one up, or do any number of tasks for which our first instinct is to reach for the keys.
NYC had a pneumatic tube system, which yes, ultimately was scrapped because it would get jammed up a lot. But it worked well enough, compared to whatever else was available, that New York City built a whole infrastructure for it. If we replaced inert capsules and compressed air with battery-powered autonomous capsules that can navigate huge runs of underground pipe, the pipes and tunnels are probably there already in a lot of cities, abandoned by the old morlocks.
The biggest problem is a failure of imagination, and the mental torpor of calcified minds. None of the above is expensive for a nation, and if we pooled our fucking tax money we could start implementing it today.