How about instead of adding "bumpers," it becomes required for a tug boat to help guide past infrastructure spans like bridges, rail, gas.

There is already something like this in use: harbor pilots, who have specialized knowledge of specific ports and board vessels to navigate them through critical transit zones. It is reported that there were pilots on board navigating at the time of the collision.

Tugs are used in tight locations, but they can only change a ship's speed at a very slow rate compared to that ship's engines. By analogy, you can pull a train car and get it moving by yourself, but if that thing is moving at 5mph you aren't stopping it by yourself in any reasonable distance.

I feel that in this situation a nearby tug boat could have diverted the ship (by at least kept it from straying from the shipping channel during power failure).

I think you're probably right. A tug (or two) hypothetically could've provided some emergency directional control.

When they reopen the port, it'll be interesting to see what early mitigations they put in place.