If you buy a cheap phone ($50 is just enough to buy a garbage cell phone in the states) then you shouldn't be upset that the carrier isn't supporting incremental updates to the phone's operating system. It might not be cost effective. Most people I know that look for cell phones on the super-cheap do not know the difference between Android 1.6 and 2.0. They probably couldn't tell you the difference between 98 and XP.

Edit: In short, I'm saying that if you cannot tell the difference and are a low-end cell phone consumer, then you can just as well do without voice search on your $50 phone. Beyond that, the good phones update themselves.