It's quite a complex issue this that I think requires legislation.
If I buy a phone I think it reasonable to get told how long my device is going to be supported and that any issues such as this that arise will be fixed. Therefore I can make an informed choice as to whether I'm going to buy the phone. This is already the case with TV's Washing Machines cars etc... and their warranty. It would be interesting to know whether the software is covered in those warranties as has been stated previously if the device is working within it's parameters then it technically isn't faulty, it may be wide open to abuse but until someone exploits it then there isn't a fault.