I used to worry about that...
I live in a pretty small city that no one really goes to unless they live near it, and the Walmart here rarely got any of the 25th Anniversary Joes and when they did, it seemed to move pretty fast. Now, they've got a full case of the the Major Bludd wave sitting on the peg that's been there for the past three days.
Really, I don't think it'll discourage stores from ordering in or displaying more. They've got room to open up a second peg, if they get more.
I don't think you'll need to worry until you see the "power wall" of Joes sitting unmoved, like so many movie lines before it. Next summer, with the movie out, will be the real test. Personally, for now, I'm happy that I'm seeing them for sale at all, outside the small comic shops.