Baffling
I really hate to be that guy, but just what do the people complaining actually play? Is the only game you play Pokemon? Cause I can name 7 good 3DS games right now that could keep you busy till October (maybe even longer). It is just a bad business move to support the DS / keep Pokemon on the DS this year. They need to push the 3DS, as it is their newest handheld. It isn't a handheld running alongside the DS, it is the next evolution of the DS, just like how the GBA was the next evolution of the GB(Color), or the DS the next evolution of the GBA.
Edit - I'd also like to add that supporting the DS at this stage means supporting limited hardware, when there is a superior product out there. By supporting the 3DS now, they are able to move the series forward. The series cannot move forward if it remains on the DS, and I don't know why anyone would prefer that option.
And to answer the question. Nope, it won't kill Pokemon. People will buy this just like how they bought a GBA or DS to play those iterations of the series. Also, if they really wanted to get their money's worth, they should stop being picky and actually see what's out there. There are a lot of games that are accessible.