... now, if Google could only find a way to be able to push out Android OS updates onto ALL handsets, regardless of manufacturers, we'd be cooking with gas.
Android's greatest asset is that it's open*. Sadly, it's also it's greatest enemy. When Google creates a new version of Android, let's say Jelly Bean, everyone should be to upgrade to it, regardless of whether HTC, Samsung, LG, etc. made the phone.
Unfortunately, the manufacturers like to tweak stuff, almost to the point where things like Facebook are tied into the sodding ROM.
If Google can find a way around this and still allow the partners to pop out the phones, then you'll soon find that the only barrier to the upgrades will be your phone simply being too old (not enough RAM, for example).
My HTC Desire will never get an OS higher than 2.2, which is a shame as the OTA update feature sounds pretty cool.
I've no idea how they could do this, but I expect those with more knowledge of how OSes work would be able to answer.
(PS - please don't say that people can just root and install a custom ROM, as the average man on the street has no idea how to do this, and it is he things like this need to consider)
* no, don't start on what Stallman thinks - it's the closest you'll get to a phone that will has a global reach without closing it up entirely. A truly open system would be so fragmented that one would become completely unrecognisable from the other.