By contrast, Chrome OS (which intentionally avoided this whole problem by taking OEMs and hardware vendors out of the update process) doesn't have this problem.

That said, it's not obvious that Android would have been able to spread as widely as it did if it had cut out the handset vendors and carriers sooner. An Android that solved that problem might not have become the Android on the majority of phones and tablets everywhere.

That's true, however, Chrome OS still suffers from the upgradability issue I described, but of course that is more of a personal rant about today's state of things and the fact that due to users' inability to easily tinker, everyone is left with devices that "just work" but will never "work" much beyond what they "worked" when they were bought (as things evolve, they will actually become less capable).

I wonder if the low market share of Windows Phone (the only OS really comparable to Android in this case, as iOS is Apple-only and all others are insignificant) has to do with OEMs not having as much control over the platform as they would like. For example, and just about looks, Android allows for things like TouchWiz and Sense, whereas as far as I know, Windows Phone does not. I have always felt that brands with both Android and WP phones to sell, don't advertise WP ones nearly as much as they could, which certainly influences the market share. In fact, with WP having a lower market share, I think it would make sense to favor advertising models with it, instead of Android ones? With the exception of Nokia of course, but that is a "special" case.