It depends on the question. If it previously didn't have an answer or only had one, it goes to the top. If it had 5 OK answers and you add a 6th really awesome one, the ranking doesn't change much - expect it to be totally ignored.
It does happen. In fact, I think that a couple of my best (and highest-voted) answers are necromancers. However, I should note that the question you linked has 51464 views. And a lot of the questions I've earned necromancer for were similarly well-viewed. That's not typical. Most old questions get a fraction of those views.
Edit: In fact, I should admit that I usually only put the effort into answering old questions when it's something that has a lot of views. It's an indication that the question is linked somewhere prominent or is ranking well for some search terms. Those questions are worth putting the time in for. Most aren't.
