Permanent losses are pretty uncommon in general. Good for them for minimizing but having bags on the next flight or delayed for a couple/three days is way more common. Probably would have to be stolen which is rare, especially in Japan, I assume or end up in some weird location without a scan.

Was flying into Narita once and I had checked luggage in part because I was carrying an award for a Japanese customer. I was sort of given a "we'll get back to you sooner or later." At which point I explained the situation to a supervisor I think and was much fluttering around and got the bag the next day.