Regardless of which step in the pipeline is the problem, Google needs to figure this out. It shouldn't be the case that Nexus phones are special either, in that they stay up to date (normally) while everyone else languishes. I don't know what the solution should be (improved portability to ease updates, contractual obligations, etc), but I do know that this leaves a bad taste in people's mouths. It's not enough for Google to say "we released the code" if no one can actually run it on their phones.

It's not terribly exciting to be running 2.3 on my Galaxy S Vibrant, for which I'm still under the 2 year contract period... (And that's with me flashing CM7 to get 2.3, otherwise I'd still be on 2.2.) Meanwhile, Apple phones update smoothly and regularly.