b1tch b1tch b1tch. androids so fragmented... damn you google, etc, etc, etc...
Apple runs both sides of the court, hardware and software, so can control aspects of updates easily. Google controls both also, but only if you buy a NEXUS device (and possibly new Motorola's). If you bought a Samsung/HTC/Sony/etc manufactured or AT&T/Sprint/Verizon/etc branded phone then don't expect updates.
The hardware manufacturers and the cell providers WANT IT THIS WAY. Why should they do work to make your existing stuff better, when so many consumers will happily shell out $600 for essentially the same hardware with a new OS.
From a developer standpoint it sucks, from a customer standpoint its wrong, from an investor standpoint its gold. Guess where these companies priorities are?
There is an easy fix for anyone not on the latest and greatest that doesn't want to buy a new phone. AOSP / Cyanogen