While I'm as annoyed at Apple as you are (environmentally friendly my arse), Android devices don't exactly have a history of frequent and timely software updates. The saving grace is that new apps often still support ancient OS releases.
Nexus One has just completely dropped support. Android's saving grace is that there is a community of programmers willing to support devices that are otherwise locked/unsupported. A lot like *nix in the early days. It's all grassroots from here on.
If only there was a way to distill that information to the less informed consumers.
The real reason here is a technical limitation. The Nexus One and many other devices from that generation have very little ROM space. Typically <500MB. ICS+ takes anywhere from 350MB-400MB of that. So the user is left is left with hardly any space to install apps. It can fit less than 5 apps probably.
Even with custom ICS and JB roms this is a problem, but there people know what they are getting into before hand, and also for rooted devices, there's ext2sd which basically uses your sdcard to store user data.
Google fixed this with Nexus S and forwards. So we have to wait and see how long the Nexus S will be updated.
If you look at the track record, they treat the current generation Nexus very well, and older models less so. Forget about ICS, the Nexus One didn't get Gingerbread for over 4 months after it was released. It did, however, get Froyo almost instantly, just like the Galaxy Nexus recently got JB almost instantly.
Not so sure about that. What happens if you need to restore your iPad 1 and redownload all the Apps? Do you get the latest version, or the latest compatible version of the App, even if the developer dropped support for your iOS version?
The latest version (if it works) - iTunes on your Mac/PC should store the latest compatible one though. Yes, it's a mess. Apple really need some kind of plan for discontinued devices. What happens when a critical flaw is discovered in Mobile Safari 5 and suddenly the 15 million iPad users are vulnerable to drive-by downloads?
They haven't done this for vulnerabilities in either 3.1.3 or 4.2.1, the other two EOL versions. I guess there probably aren't enough users of these to make them attractive to exploits, but the number of users stuck on iOS5 will likely stay in the 8 digits for a while. Whereas many people have been conditioned to buy a new phone every 24 months, I doubt this applies to iPads and iPod Touches as well. I don't know if that kind of number makes them a sufficiently attractive target for criminals.