In Soviet Russia, old platforms cost less than new ones.

Everyone has his threshold, I suppose. People also tend to be cheap, and let's not forget GB got many portable gamers used to far lower prices. Not to mention that a portable can break, be lost or stolen easier than a home device, many people don't wan't to risk losing more than a given amount of money (unless the object is a smartphone, a jewel or a watch, in those cases many people go totally batshit). I guess also screen size must be quite important for some buyers if it allows XL to be, at least in Japan (do we know how DS sales are distributed amongst teh various models elsewhere?), the best seller DS model. And heaven knows how many other reasons there could be. Also, don't think so many people are cheap, that 20-30€ cut just saved DS from losing sales and instead made it gain a puny 2% during this ad campaign that basically suggested potential DSi XL buyers to buy a 3DS instead. Anyway, both 3DS and DS grew, so, just like the ads worked for the former, the cut must have worked for the latter. In the longer term, though, all depends on Nintendo intentions about DS, but I still think killing the XL could be a mistake, its main feature gives it a market of its own.

Because not every missed DSi XL sale could automagically become a 3DS sale: there are people that actually want a DSi XL and wait for it to drop enough in price because they are just interested in a DS with bigger screen, but cheaper than what it was before the unofficial drop (for example I'm not into portable gaming, but I was interested in a XL for non gaming applications, like interactive cookbooks, particularly those that help you to decide what to prepare given the list of ingredients you have available, but now it's too late, I almost decided to switch from my old dumbphone to a cheap Android smartphone and I'll get such apps on it). Consumer electronics prices are expected to drop, but Ninty always kept XL price high, everything else dropped except it, this worked as long as it was Ninty's top end portable, but now, with 3DS drop, that pricing couldn't work as well anymore, and it also risked confusing buyers: it didn't actually happen, but what if retailers stuck to Ninty official pricing and potential buyers found on the shelves 3DS and next to it DSi XL a few euros more expensive? Some of them could have even delayed any purchase, thinking the older model was about to drop price. Having actually dropped, people can mentally position and evaluate each model better.

Um no. Nintendo needs to KILL the DS and it needs to KILL it now.

Why? It is still selling decently and will probably sell good along with the 3DS this holiday season.  I see no reason to end the DS line for at least another year or two.

Yes, I agree, that's why I wrote in another post that there must be many concurring factors, and I can just imagine very few of them.

The only numbers we have are both 3DS and DS growing during that 3DS ads campaign, despite no big recent launches for DS, but as you pointed out, these are just a few clues, we'd need at least as detailed EMEAA HW numbers as Media Create does in Japan to be able to say something more and, above all, have at least a less vague idea of how much the factors we can identify could weigh.

DSi XL is a fairly large system. It is so big that it can hardly be considered a portable system in the same way the DS and 3DS are. It is the same reason why iPad 1 is much more expensive than iPod Touch 4, and 5 when it is released.

Although, the idea that they are saying to customers "This isn't a DS, it's a next generation system" is a bit patronizing. Everyone knows this already, people aren't retarded.

I still say that Nintendo needs a complete redesign, and needs to make another full fledged 2D Mario game, instead of the 2.5D Super Mario 3D land, as well as some more of the types of games that made the original DS such a hit.

Killing the old product that could still sell for years at a lower price, but still highly profitable? About this I can't agree. But I can partially agree that the old line must be streamlined, the most of the attention must be on the new products, and the worst seller model of the old one should actually be killed. Is the worst selling in the rest of the world DS Lite like it is in Japan? Then it should be easy. Also, worst seller colours of DS should be discontinued, and more colours added to 3DS. I agree that Ninty must push more 3DS, but killing a cash cow isn't the right way, people must not have to choose 3DS because they don't offer anything else, that's not a choice. Once the price is right, games sell systems, not marketing tricks. Budget editions of old best sellers and classics for DS, new big games for 3DS and different HW prices, not to mention the number of new or improved features in the new product should be enough to make the respective targets different enough, if Sony managed to make it eventually work again (although not at the level it worked for PS2) after all the horrible mistakes it made at the beginning of this gen, why shouldn't it work for Ninty? Wait... Were you joking?  :-? 

better yet, a year before a successor launches!