Nexus devices get updates sooner and longer than other devices. I'll never buy a non-Nexus Android device until other manufacturers build up a better track record in that regard.
So Nexus devices aren't updated sooner, and they don't even receive more than one major version update. With a six-month release cycle, that means that even the Nexus devices will have a very short shelf life and will be behind very quickly.
If that's the case, then the only advantage is being able to unlock the bootloader - but that's not specific to Nexus phones, and if you still have to install a custom ROM to keep your phone up-to-date after only 6-12 months, how much of an 'advantage' is that?
The point is not whether or not there exist Nexus S devices that have received an update - the point is that most Nexus S devices have not yet received it, and are still unable to update through any official means.
And don't blame google for the messed up market in the US. Best of all is that you are not locked in some vendor version of android. Even if some carrier managed to install bejeweled on your device (again, sucks to be in the US?) that's it, you don't get a vendor specific phone-application etc. etc.
Nexus devices are getting updates sooner, they get longer support, they don't get ruined by bloatware (you might still argue that they don't get enough support, or get updates soon enough but you can't get anything better in the android world). You've tried but you seriously can't point to a single exception to that (surprised it took samsung so long to get ICS out for SGSII, it took HTC what, two weeks to roll out Froyo for the Desire?). Given the current situation the only reason I'd ever not chosing a Nexus was if I intended to use a custom rom from the get go, with a Nexus I don't have to fiddle with that.
A lot of phones released after the Nexus S will never get ICS. Regardless of whether their hardware can take it or not. HTC won't update the Desire Z (pretty much same hardware as the Desire HD (which will get ICS)) because they don't feel like updating sense for it, and without sense they can't possible give you ICS...
Can anyone even point to a phone that was released before the Nexus S but will still get ICS?
-- Nexus S 4G owner.
2) Apple upgrades older hardware with "lite" versions of their OS update. See iOS 4 for 3g (not an iOS expert, expecting corrections). No reason Google couldn't do this or at least release an optional experimental update. Sheesh, it's not like the rest of their stuff isn't beta.
They really need to get their house in order. The Nexus brand has erroded even with the hardcore fans (such as myself)
Here I am holding my beautiful but abandoned N1.