I'm not sure how the new system works exactly and I don't think it's perfectly designed but there is an explanation for the case you bring up.
Their one post was in 2008 and has since acquired over 260,000 views. Views of your threads add to your experience apparently so this is what is giving them that experience. I don't necessarily think that a user with a single post should be able to get that high but presently I'm just not worrying about it. It's a new system and it'll take some time to get the kinks worked out.