I don't blame the users. There's usually no way to upgrade android versions, so we get stuck unless we replace the phone, and most people can't afford to replace their phones so often. I'd go further and say that people shouldn't be supposed to replace their phones because of a new software version. The android's distribution model is flawed, we should be able to upgrade our phones the same way we upgrade linux distros. If it was possible, then I would blame users for running unmaintained software.