Yeah my general takeaway since E3 is that Nintendo is out of flagship games that wouldn't be follow-ups to existing products.
STEAM being the E3 showcase suggests they're working on their niches in the same way we saw them putting out things like Pandora's Tower and Xenoblade late in the Wii cycle.
This normally leads to a follow up system fairly quickly, but they did just put out the N3DS which would suggest two more years to me normally.
Not entirely sure what they're planning at this point. Perhaps third party momentum in Japan and deciding to write off the final years of the system in the West.
I'm pretty curious to see next year's 3DS support from Nintendo
So far, we know about
Codename: STEAM, which seems to me quite more "Western-oriented" than other strategic titles like...you know, Fire Emblem
The Great Pikachu Detective, still mysterious
Xenoblade Chronicles 3DS
Supposed
Zelda: Majora's Mask 3D (SO...MANY...HINTS)
Pokémon Z
Now, I think there are other titles (excluding new IPs) which could possibly come on 3DS in 2015
Rhythm Heaven, which was a bi-million seller on DS, and came out on Wii in 2011
Paper Mario: ...why not? Sticker Star sold great, and it certainly won't be a launch title for next handheld. Also, Sticker Star came out almost 2 years ago
Mario & Luigi: DS had two entries, I think 3DS could be the same. It would be released around 2 years after Dream Team, and there have been many recent sequels of 3DS titles from third parties 2 years after the first one
Remember: there are titles in development both enhanced by New 3DS AND exclusive to New 3DS. We've seen some enhanced titles, but so far we just saw one exclusive, we'll probably see more of them in the next months.
P.S. I think they're not writing off the system in the West since New 3DS is coming, I mean a brand new revision which should be a good sellers among people who already are 3DS users and want to upgrade. IMHO writing off would have been not releasing a new version at all. Especially not a new version with such significant changes / improvements. We can't say now how much it'll do in the West, but I just think writing the system off would have been something different than New 3DS, i.e. no revision at all.