I think the DS has run its course in Japan.  It's been around 100 units and was being outsold by PS2 before PS2 got discontinued there.  So why is DS still around?  It's obviously saturated and I don't see why you keep stocking it there.

Better than having leftover units sitting in a warehouse not making money.

Another 96 units added to the life time sales. The product still has demand when it sells 96 units in a week. If the product sold 0 units in a week = no demand and time to discontinue the product.

I don't see why Nintendo should discontinue the DS in Japan. Once it goes into the negatives, then we can talk. (And by negatives I mean... well, I'll let you come up with your own definition. *winks suspiciously*)

If they still have units sitting around in a warehouse over there, then there's not much point in discontinuing it yet.

When you are selling less units than the X360 in Japan I think it is time to put things to an end haha

Isnt the dsi xl still more expensive than 3ds there? That might have something to do with such low sales

For the same reason the ps2 was still being sold in America until recently. It is still selling well in some territories. So it isn't a problem to just keep some in stock in Japan. Once it is selling terribly everywhere, then they will discontinue it everywhere.

DS is almighty, it sells as much as it wants to sell, just giving some room to breathe to the new guys (Vita,3DS,WiiU) and the old geezers (PS3,WII,360,PSP) --

DS exists on a place far beyond the universe and is not limited by it.
DS knows when and how everything began... DS knows when and how the end will come.

Isn't it already discontinued in Japan? Media Create and Famitsu don't track numbers before, and I believe that's because it's no longer shipped. They stopped tracking PS2 just after it was discontinued, that's my only evidence.