Re: Why should 64 bit drive demand?
" so I don't see how it would drive demand any more than a faster GPU or marginally improved battery life would"
These are all collective increments of improvement that help show that this year's phone is better than last years. But don't forget there's three other things driving continued demand that differentiate from the PC market: Style, accidental damage, and battery degradation on sealed phones.
Style isn't about whether you have Apple or Sammy, it is just a statement that many people regard a phone as more than a utilitarian tool to be used for as long as it works. This drives replacement for the sake of replacement.
Accidental damage (and loss or theft) speak for themselves but are all useful drivers of new sales that don't look to be going away anytime soon.
And you can have the battery replaced on most sealed units, but after a couple of years most people will want to upgrade anyway - particularly if the cost of having a battery upgrade is more than a few quid.
A PC could last a decade with a modicum of care. A mobile phone has a half life of about eighteen months I'd guess, and I think the analysts recognise that because of the attritional factors, the overall market is less likely to shrink despite the increasing technological maturity, and shrinking improvements generation on generation.