I recently received the 4.1.2 update on my Optimus G, after a week of frustration from being tossed back and forth from one AT&T rep to another and then sent to LG, receiving a different answer every time for why I couldn't get it. This is the second time I have been through this experience with a "flagship phone", which are said to be first in line for the latest update. Previously I had the Samsung Skyrocket, which has also just recently received the update. The Jelly Bean update was released by Google in July of 2012 so that gives you an idea of just how long it takes to get from Google to our phones and I decided to find out why.
The most simple explanation for the amount of time it takes once released by Google is the number of times the update has to be "adjusted" for each different model and carrier. Manufacturers design phones based on what the carriers want for their customers, which is why there is a different variant of the same phone for all carriers with slightly different specs. Those slight changes have to be accounted for in the software update. In other words, Google releases the pure, untampered new OS, the manufacturers take the update and tailor it for each model, then the carrier takes it and fidgets with it more, including adding/changing the bloatware we're all stuck with.
The business model is that the newest phones with the biggest promotional push, also known as "Flagship phones", will get the most attention for updates and then they work backwards from there. Phones that sold poorly or may not be deemed as a worthy recipient of an update may be passed up. For example, a budget model from any manufacturer that doesn't boast the kind of specs that support some features of an update will probably not receive it.
AT&T is NOT the worst rated carrier at delivering software updates, surprisingly, but only Verizon was rated lower. Furthermore, here's how manufactuers fare at getting updates out for their devices, from worst to best....LG, Motorola, Samsung, HTC. Those of you eyeing the stunning new HTC One (which I wish I had waited for vs. my Optimus G), will likely have the best experience when Key Lime Pie rolls out (expected next month from Google).
The Samsung S4 will also be near the top of the list for KLP as well.
The road to improving the update process begins with manufacturers scaling back the number of devices, and carriers being more choosy about which they carry, and taking the update process into consideration. The buying process is very confusing for Android users, and really there are only 3 choices people need from each manufacturer: a budget model, a "bang for the buck" model and then the flagship model that features the latest and greatest. This would greatly reduce the turnaround time for updates as all parties involved would have fewer devices to test and tailor the software for. AT&T could take a huge leap forward by working more closely with manufacturers to learn which models are most ready for the next OS update and carry those models and promote them because all parties involved are more motivated to keep their best-sellers up to date. So, in summary, AT&T can definitely do better but for those who think they're the worst at dishing out updates, they are only one piece of the puzzle and manufacturers play their part so keep in mind which manufacturer's device you're eyeing for your next upgrade. I'd put money on the Samsung S4 and the new HTC One as the first two to get Key Lime Pie on AT&T!
I hope this has been educational and helped everyone understand what goes into a software update, and I really hope someone from AT&T reads this and passes it up the ranks.