That seems like a reach. The only substantial advantage over the DS Lite the DSi had was the camera, and the dsiware, with the huge disadvantage of dropping the GBA Slot. The N3DS on the other hand has all the same hardware support, just with the advantage of a few exclusive games like Xenoblade 3D (which is already better than most of the DSi exclusives combined), and the ability to use SNES VC. Most people now when buying a 3DS for the first time will likely either be buying a New 3DS for the exclusives, or a 2DS/Used 3DS for a lower price (in my perspective, who knows, the O3DS might still be selling like hotcakes).
Also as a side note, I'm waiting for a New 2DS nintendo.
Historically, Nintendo has always had three hardware revisions per generation of handheld console:
GameBoy-GB Pocket-GB Colour
GameBoy Advance-GBA SP-GB Micro
DS-DS Lite-DSi
I don't know if they intend to carry on this pattern (in which case, there could be
another 3DS revision in 2 years) or if the rumoured handheld portion of the NX would be the replacement. Given that the N3DS presents a much bigger jump in improvements to the original 3DS as compared to the revisions of previous consoles, the latter would seem more likely? It would be interesting to see what they have up their sleeves.
As for the original non-XL 3DS, most stores here have stopped selling new stock for them altogether. It's either second-hand O3DS, or first-hand 2DS, 3DS XL, N3DS, or N3DS XL. Not sure about other countries though.
EDIT:
Seems like even Nintendo's official Europe store has discontinued O3DS.