Author here. Anybody can drop a copy of SMB in "a" toilet, but nobody can drop one in mine. No more can or will be produced.
Of course, nobody wants a copy of SMB that has been dropped in my toilet, but my point wasn't that people are going to suddenly start collecting toilet copies of SMB, but rather that nobody was particularly interested in something as arbitrarily defined as the "highest graded, sealed, hangtab version" of SMB either until someone created a narrative that convinced them it was worth something.
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).
Of course, nobody wants a copy of SMB that has been dropped in my toilet, but my point wasn't that people are going to suddenly start collecting toilet copies of SMB, but rather that nobody was particularly interested in something as arbitrarily defined as the "highest graded, sealed, hangtab version" of SMB either until someone created a narrative that convinced them it was worth something.