A recall on a 13 year old car? I accept that environmental conditions and the laws are very different in Canada, but such action would be out of the question in Brtitain and the rest of Europe. I would go further and say it would be an unrealistic expectation.
As for surface treatment of steel against rust, that will only provide long term protection if done in the factory during manufacture, when it is possible to treat every void and hollow in the component. Such treatment after assembly of the car is impractical, possibly impossible.
Of course good design of press formed components that are not waterproof should also incorporate drainage holes so that water can escape, such as you find at the bottom of doors for example. Whether the suspension arms in question have those holes I have no idea.