>>I would rarely upgrade an operating system. Certainly with WIndows the hardware requirements usually make it pointless.

Fair enough. Meanwhile the price for a subsidized new phone already is less than the price for a grandpa OS. Maybe users really will prefer to upgrade the whole phone rather than fiddling with the innards. That seems a very likely explanation for every major manufacturer "orphaning" their phones: certainly it's better for the manufacturers if users upgrade the device and if the price is right, it's sensible for customers too.

I'm envisaging a future scenario where a security hole does appear and customers are protesting the orphaning of their Motorola phone. Motorola responds by offering a $159 upgrade to a newer handset with the latest OS, a better camera, a better screen, more memory and "Jeeves" the new speech recognition chip. For the manufacturer this may be cheaper than trying to support millions of users messing with their OS, bricking the phone, wailing about lost data, etc etc. For the user it saves the time and bother of messing with their old device and gives them an extra round of cool new technology without waiting for their contract anniversary. If this is the "worst case" scenario then it's hardly a disaster.