Price is a function of rarity and desirability. SMB is a household name so the market of individuals who would assign value to it is broader than a game like Air Raid.
Author here. I'm not being obtuse, about half of the blog post is focused on how Mario is a household name as an explanatory factor. Its odd simply because other hobbies haven't historically cared as much about that name recognition thing (which admittedly probably says more about how odd they are than about how odd it is that SMB is valuable, but still).