My general guideline (when I was able to see such info directly) was that about 20% of users were using devices more than two years old. A surprising number use five year old devices. There are (unless explicitly kicked off the system due to technical incompatibilities) users of ten year old mobiles still hanging around.
This was always just a regular part of the segmentation; after 6 months so many people will have new devices, after 18 months, you can start to expect saturation as long as a majority of devices sold have the feature, so plan your marketing and advertising budgets for the long haul.
But this BBC article on Challenges to a ‘cashless’ world brings up a good point. The lifecycle we have gotten used to for the last decade or so has stalled. Drops in sales are not just mobile manufacturers doing badly, but consumers not buying things. Aside from straight revenue losses, they are not getting the new, exciting stuff into the field.
Although so far everyone is still plenty excited about just getting their websites onto phones and still ranting about touch, what happens when someone tries to implement, say nfc to support a mobile banking initiative? Or what happens to all those wimax towers?
I actually have no idea. I think I’ve reached the end of my ability to understand macroeconomics and business strategy. But maybe I can persuade Barbara to comment on it.