The fuse swap is a temporary fix to make the cars safer until a full fix can be rolled out. I imagine truly "fixing" the leak means redesigning the ABS module, something that takes time. They need to investigate what makes the leak happen, redesign the actual part, validate that new part doesn't have some other issue, call the new part out for manufacturing (and make millions of them), get them in the hands of dealers, and then actually start replacing the part.

In the mean time, swap the fuze, and while the car is going to become immobilized or throw ABS warnings when the leak happens its not going to burn someone's house down.