I've had a phone for just over one year, and it is apparently stuck with Android 2.1 (HTC Hero on Sprint). I'd like to be excited about what Google does with Android, but they aren't solving the single biggest problem: users can't get their improvements.
At least manufacturers are starting to open up their hardware. Samsung has open sourced its drivers (SG2), Motorola is unlocking its bootloaders (Atrix), and HTC has promised to open their bootloaders for future devices (Sensation in August, future phones to be announced). Google has also recommended manufacturers support their phones up to 18 months after release, though I'm not sure how much weight that message will carry. Even if you'd rather stay away from community updates, it's nice to be given the option.
Will this ever reach phone currently running Android 2.2?
My understanding is the 3.x series is tablet only and will be merged into a 4.x series for both tablets & phones.