No denying you are having problems, and it seems like the dealerships are incompetent at fixing them. After looking at the toe numbers on your alignment, that would seem to be the case with the wandering issue. Your front wheels are not supposed to point perfectly straight forward (0°). Your toe is supposed to be ever so slightly positive, between 0.18° and 0.58° according to your picture.
Before, when you had negative toe (toe-out) and you went over a bump, a large amount of weight transferred off of one wheel and on to the opposite wheel. Because your wheel is pointed outwards, this causes the car to track in a direction away from your intended point of travel. When the weight distribution returns to normal, the other tire regains the lost downward force from the bump, and since it too is pointed away from the direction of intended travel, the car will get squirrely. This is what you felt, why it was difficult keeping the car between the lanes, and caused the wondering.
Your wheels should be ever so slightly pointed inwards (positive toe or toe-in). This causes the vehicle to track down a straight line as the wheels are ever so slightly working against each other to keep the vehicle in a straight line.
If you have been driving on tires that have been out of alignment for long enough, they will wear down in such a way no amount of alignment will ever make them feel right. My advice would be to rotate the tires, then have the dealership preform another alignment and insist all of the adjustments are dead center within the specified ranges. I would also look for more competent dealerships. If Ford insists the issue is fixed when it is not, I would push for a lemon law claim if possible, BBB report against Ford and the dealerships, etc.
It's a shame you've received such terrible service.
edit: the electric steering is not necessarily the culprit.