I hope I don't post this in the wrong place.
It's been known for the life of Android that upgradability of the device is one of main reason when deciding to buy a device. Among the main stream brands, I have owned Samsung Galaxy (the first Samsung Galaxy), LG Optimus G and first generation of (ASUS made) Nexus 7.
Nexus 7 still receives updates until now. I received one or two updates for my Samsung Galaxy and I never got any update on LG Optimus G. According to media, Kitkat update for LG Optimus G is coming (or has come in some countries) but I have not seen it so far.
I have also owned and used few Chinese brand Android devices and they are good for the price but again the version came with the device is pretty much what you will end up with.
My question is: how hard it is to produce an Android phone that can run Vanilla Android and some future updates (within reasonable time frame). I don't know anything about OS level programming but I would imagine that Google must have some guideline and roadmap about OS Android. If Nexus devices are updatable, why can't other manufacturers choose the same kind of hardware? Can anyone who knows about how OS/hardware working share their knowledge?
It would be awesome if Chinese devices run Vanilla Android and are updatable just as Nexus ones.
[EDIT] I guess, my other question is: is updatability (or lack of it) more a technical or business reason?
Thanks.