There are two down points here.
First, "Linked Questions" only lists the questions, but it will list a question if a specific answer has been linked. So if we worked off of the same tracking system, we would notify the question author when an answer was linked. Very confusing. This is the easily handled down point, of course - highlight the author of the post instead of using the Linked Questions section mechanism.
Second, this is very problematic for exemplary posts which either are used as examples often, or happen to be duplicated often. I know I've seen a number of posts that are linked often because of how useful the answer is. I imagine the author has no desire to be alerted every time someone else posted a duplicate of their question. And the umpteenth time an expert gets alerted that someone found their solution useful would probably also be tired.
In the end, the relation between a post being merely linked and whether it is interesting activity to the original author is not very strong. Not strong enough to warrant mechanical alerts, in my opinion.