This isn't that uncommon in North America from what I have seen ...
Outside of electronics and videogame stores, which have massive inventory space, most retailers have very limited shelf space for games. Typically, when they reclaim shelf space from one game they (seem to) send it back to their warehouse where it is (eventually) reallocated for bargain bins. On occasion, when everyone is dramatically overstocked with a game you will see a fairly new game in the bargain bin.
Now, in Japan this could be more common because retailers may be run differently ... Hypothetically speaking, if you're manager in a store and you're (entirely) responsible for the sales of your stock you might choose to put an overstocked game in the bargain bin at what it cost you to buy it soon after release rather than wait until it is worth less than your cost.
