Actually, looking at the NDS numbers, I'm a bit baffled by how fast Nintendo went with the change of the NDS to the 3DS the following. It was still posting insane numbers at that time
without the announcement of 3DS in 2010 (and maybe releasing it a little bit later), I am sure the DS could end with 2-3M more that year and entering stronger in 2011.
They should have released the 3DS in holiday 2011, not in February. That way they could've launched it with Super Mario 3D Land and Mario Kart 7 and it would've started out stronger. Instead they originally planned to launch it in holiday 2010.
True, but I think Nintendo had their eye on Sony releasing the Vita in holiday 2011 and wanted to have a new handheld on the market before then. Sony had gained an impressive foothold in the handheld space with the PSP, so Nintendo likely wanted to get a headstart on the next generation of handheld tech. The same way they cut the legs out from under the Gameboy Advance, which had sold well in a very short period of time, in order to counter Sony's launch of the PSP.