That sounds like a horrible idea logistically, you still need to ship stuff from a cargo terminal to the location its needed and putting single containers on rail as their own "train" makes traffic a absolute nightmare there will never not be some kind of truck unless we can Teleport shit around or airships become a cheap, fast and reliable option.
The problem is mostly that we don't build rail spurs in industrial areas anymore. If we did, then these cars could detach from trains at a shunting yard, and split up to head to all their different destinations individually. But the only last-mile infrastructure we currently have is roads.