If you have a shortage you create a greater demand.
Kind of strange really, but people who may not have wanted one straight away will now probably try to buy 1 straight away in fear of not getting one.
i would be pretty surprised if there was any other reason behind there being a shortage other than to boost demand, with how things have been going in the cpu world the past few years there really is not that much incentive for people to buy the newest cpu on release.
but if you were considering it and then you hear they will be in short supply it may just be enough to tip you over the edge and buy one asap.