Not really. Hype will certainly die down from now to the time it launches, but within months of its release it'll be back in TV shows, media, whatnot. People seem to forget that games often announced up to 5 years before release still have fantastic sales and even more hype then ever because of it. i.e. Gran Turismo 5 and FFXIII will probably have fantastic sales, and they were announced long ago.
but they didn't say any date, so i think it will last 2 year even longer at least. then perhaps sony has his motion thing and even more peole have the wii.... nobody will buy it if its release takes too long..