I am going to go out on a limb here and hazard a guess that the number of people willing to hang out on Android forums and hassle with rooting the phone to install a new version of the OS is vanishingly small compared to the number of people who couldn't tell you who made their phone, much less what version of the OS it runs.

That said the fact that a new Android release has to pass through two other sets of hands before it can get to an end user sure ain't helping.